Everything you need to know about the AltMill

Hey guys, it’s Andy here. We’re excited to be launching a new CNC machine, the AltMill! This article is designed to tell you everything about the AltMill that we possibly can.

Dragon and Phoenix Carving

What is the AltMill?

The AltMill name is derived from “alternative”, “alter”, and “mill”. We believe that “alternative” fits the namesake of the AltMill because this machine represents a different way of approaching things in engineering, technology, and the way we build our company as a whole. We believe “alter” fits the purpose of the machine, which is to take materials and alter them into new forms, uses, and purposes. And of course, since we use milling as our way of altering the material, we can put these ideas and words together to form the name “AltMill”.

The AltMill is a culmination of new technologies, hardware, experience in manufacturing, and customer feedback. Our goal was to take all of these things and build a machine we felt brought the most value to the CNC user by incorporating our ability to engineer high-performance, quality machines at scale.

Differences and Similarities Between the AltMill and the LongMill

The focus for the LongMill was to be a medium-format, hobby-focused CNC machine. Most users typically are looking to make things with a CNC in their spare time. Because of this, we made the LongMill the most affordable option possible in this size category, while being useful and effective enough to handle just about any CNC woodworking project you want to throw at it. We define LongMill’s success in its ability to make CNCing accessible to the average person.

The AltMill is designed to have the most “effective value” as possible. Its success is defined by how much value it can create versus the cost of the machine itself. In simple terms, we wanted the machine that would bring the highest ROI and productivity. The AltMill focuses on the intersection where we believe the performance versus cost ratio is the highest it can be for these users.

Here are some spec comparisons to highlight the differences between AltMill and LongMill:

  • We’ve tested the AltMill to over 830IPM (although regular cutting speeds are in the 250 to 500IPM range) in cutting speed, while most projects we run on the LongMill run at 100IPM.
  • Based on our deflection testing, the AltMill is approximately 8x more rigid than the LongMill.
  • While the LongMill’s main bottleneck in cutting speed is in motor power and rigidity, the AltMill’s bottlenecks are in spindle power and the strength of the endmills. We estimate that the AltMill could handle upwards of 6KW of spindle power (although it’s not likely we’ll dive into that anytime soon because there are a lot more expensive electrical requirements we need to tackle to get this set up for the average user).

That being said, there is an overlap between these two machines. The process of using the AltMill is basically the same as the LongMill, which means that our resources and education translate over between the two machines, and the ease of use and process of using of both is similar. Additionally, both machines are designed primarily for woodworking use, and the types of projects we expect users to create will be similar as well.

Should I get the AltMill or the LongMill?

This depends primarily on your budget and what you want to do with the machine.

Here’s why you would want a LongMill:

  • You are budget-conscious. The total setup cost for the LongMill is roughly half the cost of an AltMill. Additionally, replacement parts and maintenance is cheaper overall.
  • You have limited power in your shop. We recommend having two breakers to power your LongMill and accessories such as the computer and dust collection, but in some cases, you can get away with one. On the other hand, you may need to connect the machine, dust collection, and spindle on separate breakers depending on power availability in your shop.

On the other hand, here’s why you would want an AltMill:

  • You need speed. The AltMill can cut significantly faster than the LongMill. We regularly run the AltMill over 5x the recommended milling speeds compared to the LongMill. The productivity of the AltMill is much higher.
  • You need more working area. The largest version of the LongMill has a working area of 48×30″, whereas the AltMill can cut 48×48″. This means you can process half of a standard 4×8′ sheet in one setup.
  • You need more precision. With ball screws and linear guides, the overall precision of the AltMill is better. In practice this may not matter as much with woodworking projects, you may see a bigger difference in the accuracy of parts for materials like aluminum.

AltMill Budgeting

Of course, the higher performance of the AltMill comes at a cost. We discussed the breakdown of costs one should expect with the LongMill in our article here. Here are some rough estimates on what you should budget (in USD).

Based on my estimates, you should budget around $4500USD to fully set up an AltMill from scratch, about double the cost of the LongMill. You may have some of these items already which will lower your costs.


The machine itself ($2950USD)

This is the machine and all the doo-dads to have a working machine, minus the spindle, wasteboard, and computer.

Unlike the LongMill, the AltMill comes default with table legs, so you don’t need to build a bench for it. Additionally, the AltMill comes with inductive homing sensors by default.

Based on our rough estimates, shipping within US and Canada should cost between $150 to $200USD.

Spindle and dust shoe ($515USD)

We recommend users to use a spindle with their machine, because running the Makita router on the AltMill will make the life of the router very very short and unenjoyable. We expect the majority of users to order the Spindle and Dust Shoe Kit which we offer as an add-on kit.

For users wanting to add their own spindle, we expect after all of the parts, wiring, and extra things you’ll need with the machine, it’ll run around $500USD on the low end, but could cost up to a few thousand dollars for some really high end spindles.

We are offering a 1.5KW 110V spindle at this time because we believe it will accompany the most number of people at the launch of the AltMill. However, we will likely offer higher-powered spindles requiring 220V in the future. Users planning to implement higher power spindles should also budget the cost of hiring an electrician for any extra work.

Dust collection ($300 to $1000USD)

Assuming you get the Spindle and Dust Shoe Kit from us, the dust shoe comes with a 4″ hose mount. To get the full performance from the AltMill dust shoe and to keep up with the cutting rate of the machine, a dedicated dust collector should be used. A regular shop-vac can be used, but may not be able to keep up with the waste material generated by the AltMill when running quickly.

Computer ($250 to $800USD)

The AltMill and the LongMill share the same system requirements, which can be found on the System Requirements page in our Resources.

At minimum, you will need a computer to run gSender to control the machine.

Wasteboard ($50USD)

Like the LongMill, you will need to mount a wasteboard to the machine. A 4x4ft sheet of 3/4″ is recommended as the base. On the AltMill, the wasteboard is mounted to it’s frame using screws. You can additionally purchase t-tracks if you wish to add some workholding to the wasteboard directly.

Tooling ($100-200USD)

You’ll also probably want to order some endmills and bits for your machine. You can use the same tools between the LongMill and AltMill, although we will likely expand our range of endmills to accommodate the larger collet sizes we can use with the AltMill spindle. Tooling costs vary widely, but we sell affordable end mills on our store.

Software ($0USD to $699USD)

The AltMill works with our free gSender for all of your machine control needs, along with additional features such as machine calibration, firmware changes and updates, surfacing g-code generation, and more.

For CAM, all of the software that works with the LongMill also works with the AltMill. You can learn more from our Software Resources. There are both many free and paid software options for the AltMill.

The most popular software, and the one we recommend frequently is VCarve Pro, which offers advanced 2D and some 3D carving features, flip-milling set-ups, 4th axis support, and more. This software has a one-time cost of $699USD.

What to Expect When You Get an AltMill

Please note that at the time of writing, we are starting the first production run of the AltMill. You may find relevant information about the Order Status page or in our Production Updates in the blog.

Shipping and Delivery

The AltMill comes in three large boxes. They have been specially designed to fit compactly to reduce shipping costs as much as possible. We estimate each box will weigh about 70lbs. With UPS or other courier shipping, you should expect transit times within the US and Canada to take around 1 week.

Packaging mockup

Based on some general shipping cost calculations, customers should expect to pay around $150-250USD for shipping within the US and Canada for an AltMill.

Set up and Assembly

Large portions of the machine will come pre-assembled, but final assembly of joining the sub-assemblies will be necessary. Most of the machine is put together with M5 and M6 screws, and a set of metric bits or allen keys are required to finish the assembly. Additionally, you will need to provide and mount your own wasteboard. We recommend using 3/4″ MDF.

We will have resources to help users set up and assemble their AltMill on our Resources in a similar style to the LongMill and other products we’ve created. Users should allocate between 3-5 hours for the assembly and set up.

Users will also need to provide a computer that can run gSender. More information about downloading gSender and details about its setup can be found in the gSender Resources.


The AltMill works just like the LongMill and most other CNC machines. We’ll provide more guides on setting up the machine for different types of work. Beginner users may find content in the LongMill Resources relevant. We expect this group of users to be a bit more advanced, and some of the content and information will reflect this. Additionally, users should expect revised content such as updated feed and speeds and installation for the add-ons to come soon.


The AltMill maintenance is simple, but needs to be done regularly to prevent damage to some of its components and have optimal performance and longevity.

Here are some estimates for bearing maintenance:

  • Ball screw and supporting bearing components should be greased every 3000-5000 hours, or a small amount of greasing done more frequently
  • Linear guides should be wiped and oiled for every 100km of use. With full-time use, users should oil their linear guides every 3 to 4 weeks.

We will provide thorough resources and guides to perform proper maintenance for the AltMill.


Extrusion Design

The process of designing the LongMill extrusions gave us a lot of experience in designing extrusions for high precision and rigidity critical applications. Since then, we’ve used this knowledge to manufacture parts such as the t-tracks and the enclosures for the SLB. This experience was able to help us understand the quirks and strengths of aluminum extrusion in the construction of the AltMill.

The AltMill extrusions are big, especially compared to the LongMill, which lends to its strength and rigidity. If you want to check out the video where we talk about this more, see it below:

Clip from the video

To make sure that the frame and axis of the AltMill are straight, a few additional steps have been incorporated to make extract as much performance and accuracy from the extrusion as possible.

First is in our process of extruding and milling the critical surfaces flat. Once the extrusion is pressed, it gets annealed and straightened, which allows for fairly high tolerances. However, there can still be sub-tenths of a millimetre deviations in the tolerance and straightness of the extrusion. To eliminate this, mounting surfaces for the linear guides and the ends of the extrusions have been machined to ensure they are flat and parallel.

Second, additional extrusions that make up the base of the machine are designed to help keep the Y-axis rails straight and parallel. Each of the bottom rail ends have been machined to make sure they are of an exact length, so the distance between the two Y rails is extremely accurate. This also provides additional support and rigidity to the machine, plus having mounting points to make it easy to add a wasteboard to the machine.

Test assembly of the AltMill “bench”

Users will find that the extrusions also come with many different design aspects, such as t-tracks and mounting points for motor components, legs, drag chains, and more, allowing the machine to be easier to assemble and maintain while saving costs by reducing the number of parts needed to build the machine.

Design for Shipping

One of the challenges that come from getting a CNC machine, especially a large one, is getting it from the factory to the door. Most machines in this range do need to be shipped in multiple boxes and the AltMill is no exception.

To make it as inexpensive as possible to ship, we have made a lot of considerations such as:

  • How can we maximize the travel of all of the axis while keeping the rails as short as possible?
  • How can we keep the weight of the machine low while being structurally rigid?
  • What items are we going to make default or optional, and how will we design the packaging around these considerations?
  • What sort of weight and size can the packages be and how will it affect handling?

The AltMill is designed to come in 3 large boxes weighing around 60 to 70lbs each.

Design for Assembly

Because of the more complicated procedure for assembly of the AltMill, a lot of consideration was made to make the machine as easy to assemble as possible internally. Here are some considerations for the design for assembly:

  • Mounting surfaces for high-precision components like the linear guides and bearing blocks are machined and toleranced to help initial assembly onto the rails and gantries pre-aligned.
  • We’ve worked with our fasteners manufacturer to use custom make screws with pre-applied thread locker, reducing the chance of screws coming out from vibration and avoid the need to apply thread locker manually
  • Reutilization of linear guide assembly procedure, testing, and torquing of screws to ensure smooth movement of the assembly used in the LongMill Z-axis.
Machining tolerances for the AltMill X-axis
Back of the X-axis gantry where the linear guide blocks mount

Linear Guides and Ball Screws

One of the biggest differentiators between the LongMill and the AltMill comes from the use of linear guides and ball screws. While the LongMill’s v-wheels and lead screws offer an affordable, simple, and forgiving linear motion experience, ball screws and linear guides offer another step above in precision and rigidity.

Our ability to integrate linear guides and ball screws comes from a few different areas of expertise we’ve developed over the years and additional research and testing we’ve done in this project.

Linear guides and ball screws are much more expensive than v-wheels and lead screws. However, we have been able to source them at a lower cost because we are able to order them in larger quantities. For context, ordering them at wholesale can cost 1/3 or less than retail prices, and we can pass those savings onto the customer. Second is our ability to understand the differences and context of the cost and in-practice differences between different linear motion components. The AltMill doesn’t use the highest-end, most expensive components because we know that for our users, they won’t experience or notice the benefits of it. By being able to balance cost and performance, we’re able to choose the right components for our application.

We’ve also had the chance to work with different linear motion components in the production of the LongMill Z-axis, as well as through other internal projects. Through this experience, we’ve been able to better understand the process of assembling and working with different linear motion components at scale, see firsthand the results of long term use and lack of maintence through LongMill users, and test linear motion parts from different designs and manufacturers.

We do expect some new challenges with working with linear guides and ball screws, mainly in educating users on proper maintenance of these components. While these components can last a very long time, proper cleaning and lubrication is critical to make sure they perform properly. From our experience, the biggest factor in the longevity of these components is in the proper lubrication. It should be noted that one of the main downsides of using bearing-based linear motion components is that lack of lubrication can dramatically accelerate wear and cause catastrophic damage. To mitigate this, we plan to provide proper instruction and lubrication supplies to make it easy for users to perform proper maintenance for their machines.

Tramming Functionality

For those who aren’t familiar, tramming is the process of adjusting the position of the router or spindle, typically by tiling it forwards and backwards, and/or left to right. This ensures that the cutting tool stays aligned with the Z-axis. Having a machine out-of-tram can result in things such as ridges or artifacts, especially on surfacing operations with wider bits.

The AltMill, as far as we’ve been able to find, is the first hobby CNC machine to have nod adjustment, allowing for the X-axis rail to tilt slightly forwards and backwards, eliminating the need to shim the spindle mount. Additionally, the AltMill offers tramming on the spindle mount, which allows the user to move the mount left and right slightly as well.

A combination of an eccentric bushing and shoulder bolts are used in the Y gantry and X-axis to provide nod adjustment (bolt removed for clarity)
Similar to the nod adjustment, the router mount uses an eccentric bushing to adjust left-right alignment

I should note that the eccentric bushings are only used for tramming. In the regular set-up, they have a bolt securing through them, or a shoulder bolt which aligns them to the gantry by default. Also, I should note that currently the tramming for the Z-axis is only built into the default 80mm mount. We do have mounting options for the LongMill 65mm mount, but this does not have tramming.

It should be noted that having the machine assembled in the default position will be within spec enough for virtually all users. Most of the relevant parts are machined to very high tolerances, and there are also many reference mounting points and hardware to help have the machine aligned and straight out of the factory in the assembly process. It is unlikely users will be able to easily make meaningful adjustments without tools like a tramming tool or gauge and a surface plate, and we recommend keeping the machine at its default position.

Why did we add this as a feature? To be completely honest, I hadn’t even thought about it, but one day when I asked Daniel if he’d thought about it, he just shrugged and said he designed the whole thing just for the heck of it.


While the SLB initially started off as a project for the LongMill, many of the technologies and improvements will be present in the AltMill as well. We are currently in the development of a new version of the SLB (code named ALT-SLB or SLT-EXT) that will allow the use of external drivers that the AltMill uses for its motion system.

SLB-EXT, with plugs for external drivers

The main focus of the SLB was to improve stability and reliability of the LongMill’s motion control. We believe the development in this area will translate to rock-solid connection between gSender and the controller. Additionally, on-going development to have a dedicated, on-board computer will be able to be used for both the AltMill and LongMill.

There are some other important aspects and features that we believe are very relevant for the AltMill, including*:

  • RS485 Spindle control
  • Communication between the controller and computer using Ethernet and USB-C
  • Programmable physical buttons to trigger g-code commands and functions such as homing, moving the machine to a corner, and more
  • Tool Length Sensor and Tool Changer support
  • Ability to manage more pulses per second for higher motor speeds
  • Squaring and calibration functionality
  • Full independent 4th axis support

*Please note that some of these features are in-progress and are not ready for release yet.

Along with the “brains” of the board, we are also working on an external power-switching system to distribute power to the motors and interface with the e-stop to ensure the power is cut completely in the case of an emergency.

It should be noted that the SLB and the SLB-EXT are not interchangeable. The SLB is primarily focused on being a controller designed to be plug-and-play with the existing motors on the LongMill, and does not support external drivers for the X,Y, and Z axis. The SLB-EXT does not have integrated stepper drivers on board and must use external drivers.

48V Power Supply

During the pandemic, due to the chip shortage, the original power supply that we were using for the LongMill became extremely expensive due to a specific chip needed for manufacturing. Because of this, we spend a lot of time looking into alternative power supply designs. By switching to a design more commonly used in lighting applications, not only were we able to decrease the cost of the stepper motors, we were able to improve the reliability of the power supply because we were able to internally encapsulate the components to protect it against moisture and vibration. Additionally, we were able to more easily make larger power supplies because of the improved heat dissipation properties of the new power supply.

With this change, we’ve seen a dramatic decrease in power supply-related issues for the LongMill while being able to provide more than 20% more power than the previous design. The AltMill power supply offers nearly double the power of the LongMill power supply at 48V, which allows for additional benefits.

The main benefit of a 48V system is the ability to run the motors faster. Stepper motors lose torque the faster they turn, which means that the faster the machine moves, the more likely it is to lose steps. Increasing the voltage allows stepper motors to “flatten” the torque curve, allowing more torque at higher speeds. With our initial testing with open-loop steppers, we were able to see some small gains in motor speed by about 20%.

Closed-loop stepper motors

When we first started prototyping and testing the AltMill, we quickly found out that one of our bottlenecks was the speed of the open-loop steppers we were using. Over the last few years, the technologies behind motor control has greatly improved, and the cost of these components has come down as well. Additionally, because of our ability to purchase the components at a higher volume, we’re able to also make the machine as a whole more affordable as well.

Closed-loop steppers are motors with an encoder that provide the driver with feedback on the position of the motor. With this information, the driver can correct the position of the motor in real-time, compensating for lost steps and adjusting power consumption based on speed and load.

With the LongMill open loop steppers at 48V, we were able to hit speeds of around 4000-5000mm/min. With the new closed-loop motors, we were able move the machine at around 25,000mm/min before the ball screws start vibrating and jam up the machine. We were also able to push the AltMill all they way to 5000mm/min^2 acceleration rates, 6-7 times higher than the LongMill’s defaults.

There are a number of additional features that make the closed-loop steppers an exciting part of the AltMill because:

  • The motors can detect crashes and jams, then send an alarm to the controller to automatically shut down the power and spindle down, making the machine safer
  • Because of the higher efficiency, they can run cooler and a smaller power supply than what an equivalent open-loop stepper system would need
  • Noise and vibration are generally lower

Spindles and VFDs

Given how powerful the AltMill is, having a spindle is a must. Looking into different spindle options has continued to allow us to look into many different considerations when it comes to picking the right one.

Testing deflection on a spindle

As I talked about in the past in this article, the quality of different spindles varies widely. Because of this, we’ve been hesitant in offering a spindle option since we knew there would need to be a lot of work involved in finding the right manufacturer for it. However, now that we need to get one for the AltMill, we’ve learned a lot about them. Here are some of the considerations about the spindle sourcing including:

  • The bearing quality, size, and configuration and how it affects the longevity of the spindle
  • The deflection from the spindle itself
  • Cost and availability
  • Cable quality and durability
  • EMI
  • Communication protocol like PWM, analog 0-10V, and RS485
  • VFD efficiency and control technologies like vector control
  • Programmability and ease of use of the VFD
  • Collet quality and size
  • Runout

We have a pile of VFDs and spindles in the testing phase. We haven’t settled on a specific combination yet, but we are planning on choosing one soon.

At launch, we plan to offer a 1.5KW 110V spindle that can run off a regular North American outlet. We are currently in the process of testing a 4KW spindle option that will require more power.

Table Legs

One of the main reasons why we didn’t end up making a 4×4′ LongMill is because we would need to move away from the “mount the machine to a big piece of MDF” design. Basically, since the machine needs to be larger than it’s working area. If we wanted to go for a 4×4′ working area, the material the LongMill sits on would need to be a bit larger (probably around 6×6′).

I should also add here that the main reason we chose a 4×4′ working area for the AltMill is because most standard sheet goods like plywood and MDF come in 4×8′ sizes, so the AltMill can process half the sheet at a time. I should also note that because of the back end of the machine is open, you can pass materials through the back, so you can put the full sheet on, cut into it, and move it out the other end without cutting it in half.

AltMill table mockup

If we were to have the AltMill come without legs, users would need to have a larger bench, also about 6ft wide and long, to accommodate. If you took two 6ft wide workbenches from your hardware store and put two of them together, you’d probably be paying around $800 for the pair. The extra legs on the otherhand, cost about $150USD and are made from bent and welded sheet metal in a local shop near us.

Additionally, the AltMill carries a lot more inertia when it moves, which means that the structure it sits on needs to be as solid as possible. This is why a lot of industrial machines use cast steel and welded steel frames, since the mass of its structure dampens the movement and reduces vibration. Of course, we’re not getting into that realm, but we knew that if we built our own table legs, we could make sure it was to the specifications and level of stability we would want to see users have by default. Additionally, we wanted to take the chance to build in a few extra features including:

  • The ability to add extra shelves underneath by screwing in some extra 2x4s to the pre-cut holes. These shelves are also designed to be 4ft wide at the front, so you can keep half sheets of material under the machine. Having the extra cross bracing adds more stability to the structure as well.
  • Add leveling feet, to make sure that each side of the table is contacting the ground, to avoid wobbling. These could potentially be swapped for casters, so the machine can get moved around.
  • Add mounting points for other items such as the VFD and e-stop (still in progress to solidify exact positioning)

We’ve found that at some really high accelerations and fast movements, the machine can “walk”, and so we’ve been considering sandbagging the machine to see if we can up the speeds even further. It’s probably not practical, but something of consideration.


One of the things I sort of realized is that for most hobbyists and beginner-level users, it’s hard to get context on how much “performance” a CNC machine has. So We figured that the best way to show it was to film videos on the machine doing stuff. So here are some videos below.

Here’s also another non-scientific test.

Daniel standing on the Z axis of the AltMill

Here are also some of Daniel’s notes about the rigidity, which should provide some context on where the AltMill stands based on his estimates. I should note that these are just rough estimates based on calculations from tests done by other users, so they may be incorrect.

Market and Competition

I see a lot of similarities between the launch of the original LongMill and the original AltMill in a number of ways. When the LongMill was first launched, it competed directly against machines such as the Shapeoko 3 and the XCarve. At that time, there were a lot fewer hobby CNC companies, and those were the most popular machines at the time. At this stage, cost was a really important barrier for people to get into the hobby, and we knew we needed to design something robust enough for people to use the machine to make valuable products while being affordable enough to get that ROI back as soon as possible.

An interview video with one of our first beta testers for the first generation of the LongMill

First, we made the LongMill design as simple as possible. This allowed us to have fewer parts, which not only reduced the cost overall, but made it easier to pack, assemble, and ship the machines. Second, we tackled the most common complaint and limiting factor that users (including Keith) complained about, which was the use of belts. By using leadscrews on the LongMill, we made this machine an even more compelling option. Even though our company was not very well known at this point, I believe that a combination of our approach to designing a better machine at nearly half the cost of the competition got a lot of new users on board into the hobby.

The idea of a 4×4′ CNC router table isn’t unique. In this market, the AltMill competes directly with machines like the Onefinity Elite Series, Shapeoko 5 Pro, Shapeoko HDM, and XCarve Pro Series as a mid to high-end CNC hobby router. However, by reading and studying the feedback from users of all of these machines, we’re able to focus on addressing these things in the AltMill design itself. I won’t go into them here in this article specifically, but some examples include:

  • Using closed-loop steppers to eliminate the issue of losing steps
  • SLB and SLB-EX development to address static and EMI-related control issues
  • Plug and play 4th-axis option

Additionally, although the price difference between the AltMill and it’s direct competitors is not as dramatic as it was for the LongMill, it is still priced extremely competitively and minimum $1000USD less expensive than it’s closest priced counterparts.

Moving beyond that, we believe that the AltMill may have some customers looking for high-end hobby to semi-industrial machines who are also considering the Avid PRO4848, Phantom SC44 and StepCraft Q.404CNC. These are machines in the $8000-13,000USD price range.

Just to be clear, the AltMill is not a direct competitor or replacement for a semi-industrial or industrial machine. A lot of these higher-end machines may have things like welded steel frames, which is technically better for high-speed cutting. In practice though, there is still a lot of overlap because both machines can do the same projects and run at pretty high speeds.

I sent an email to Avid to ask about the specs for the PRO4848 and this was the response:

In any case, Daniel and I had a long discussion about where the AltMill falls. It feels like the AltMill with its speed, power, and price, blows all of the hobbyist-level machines out of the water. When comparing the AltMill to some of the upper-level machines, the distinction between them also starts to shrink.

Here are some of my final thoughts:

  • If you’re looking for a hobby machine in the $3000-6000USD range, the AltMill has the highest performance in this category
  • If you’re considering a semi-industrial machine above the $6000USD range, all the way to around $15,000USD, an AltMill might still work for your application, or you can buy more than one to double your production ability.

There are a few areas I do feel like we need to work on to make the AltMill even more compelling and competitive which include:

  • An onboard computer and touch screen, similar to the Masso controller. At this current time, we are working on our own computer and touchscreen setup, and expect to have more news in the coming months
  • A more powerful spindle option around 3-5KW
  • Toolchanger
  • More advanced work holding system, such as a vacuum table.
  • Larger machine options

Future Goals for the AltMill

Engineering Trickle up and Trickle down

There is a lot of engineering that can be transferred between the lower end of our product line (the LongMill) from the AltMill to make improvements, as well a lot of things we learned from the LongMill in the manufacturing of the AltMill.

Some AltMill development that may trickle into LongMill include:

  • Toolchanger
  • 3 phase spindle options
  • Z-axis and router mount designs
  • Bench/table designs

Some LongMill developments that may trickle into, or have already impacted the AltMill feature set include:

  • SLB features, such as USB-C and Ethernet, RS485, tool length sensor input, physical macro button support, external relay control, improved laser rastering, and more
  • Extrusion manufacturing and quality control processes
  • Customer service and resource development processes

Additionally, as we make more volume of each new product and technology, we can bring the price point and improve accessiblity because we can leverage economies of scale and the fact that the work of each project impacts more people overall.

New Markets and Verticals

So a bit of backstory. Sometime last year, we started rediscussing the potential of designing and developing a new machine. From this discussion, we had three contenders, the AltMill, the CO2 laser, and some sort of mill dedicated to milling metals. The decision was made that we should try to make all of them, one way or another. Both the AltMill and the CO2 laser are in development now, which leaves the metal milling machine project still up in the air.

Just for a bit of context, the engineering team had a general idea of making something similar to the Langmuir MR1, or basically an affordable, hobby-level gantry mill.

The plan was to make the AltMill first, and shrink the AltMill down to make our a gantry mill using the same core parts and electronics. Based on Daniel’s testing on material removal rates, it looks pretty promising we can build a competitive machine in this realm.

In my travels in the past year to Brazil and China, one of the gaps that I’ve seen has been in the way CNC machines such as VMCs are used for production. While large industrial machines have their place in making high-precision parts, their running costs are high, even if the parts are small, of lower value, or don’t require small tolerances. The idea is, rather than using expensive big machines all the time, smaller, less expensive machines could be used for milling batches of smaller, lower tolerance parts. Additionally, factories install and use several machines for the space and cost of one large machine to scale up their throughput.

The team and I have a lot of interest in exploring this avenue next, I expect the things we learn from AltMill design and production will help us tackle this new vertical.

That’s not to say we have some other things on the docket of considerations, such as:

  • Making a machine to target hobbists looking for a machine option below the LongMill’s pricepoint, size, and capability like the Mill One Plus.
  • A larger version of the AltMill for 4×8′ cutting
  • New accessories for the AltMill and LongMill, as well as support for other machines outside of our ecosystem

We’ll probably worry more about this after the launch and first production of the AltMill. But if you want to share your thoughts about what you want to see come from us in the future, make sure to share it through our form.


Here are a list of questions people have been asking us. Please note that there are more FAQs on the main AltMill landing page.

Will the Spindle Kit be available for sale on its own?

A lot of people, especially LongMill owners, have been asking about if the spindle kit for the AltMill will be available as a separate option. The short answer is, yes, because we won’t stop people from buying stuff from us if they really want to. However there are a few things to consider.

First is that the 80mm spindle is pretty big and heavy. There is some testing and validation we’d want to do before making it an “official” LongMill spindle option because of this.

Second is that we’re also working on a “Sienci Router”, which we plan to launch in the next couple months, which will be a drop in replacement for the Makita router, with speed control, and a brushless motor that allows for around 800 to 1000 watts of usable power, or around double the power output of the standard Makita router, which will be cheaper, lighter, and more suitable for the LongMill.

I do recognize that at around $500USD, this spindle kit still offers a lot of value, and is priced competitively compared to other, plug-and-play kits. I think there will be a number of people outside of the LongMill and AltMill ecosystem that we can serve with this kit as well, so we will explore that option in the future.

Why offer a 1.5KW spindle when the AltMill can handle a 2.2KW or larger spindle?

Based on our testing between a number of 1.5KW and 2.2KW spindles, we felt like the power difference between these two options were not large enough to justify the extra complexity of having the extra 220VAC wiring. We are continuing to do both real-life testing and establishing a bench test to measure the true output of the spindle.

Based on our estimates, to get the full potential from the AltMill, a 3-5KW spindle would be best suited for the machine. However, most households would need to invest in having an electrician set up the appropriate power outlets installed to allow this use.

This comes to another question, which is “how powerful do we really need to make the AltMill”? The other bottleneck that we need to address is the strength of the end mills. Based on our real-life testing, another reoccurring issue is that if we run the job too fast, the end mills break. For us to cut even faster, we’d need to use larger-diameter end mills. In some cases, this may be useful, such as in projects like surfacing and boring lots of material, but this is a small subset, and may not make sense to offer a spindle designed to do that all-day, every-day, if the alternative is to slow down the machine during these types of jobs.

Will you be making a larger/smaller AltMill?

Very likely yes, since the AltMill offers a platform that can be made larger or smaller by changing the size of the rails and linear motion parts, as well as mixing and matching some of the components. Making a smaller machine is probably the easiest, since it doesn’t have the same problems as making a larger machine, as we will discuss next, and we have some ideas for making a machine more dedicated to milling smaller projects or metals, similar to the Langmuir MR1.

There are two main challenges to making a larger machine, which in this case is probably going to be a machine that is for cutting 4×8′ sheets. The first is in the power transmission system for the Y axis. The longer the ball screws get, the more prone to “whipping” there is, especially at higher speeds. To avoid whipping, we would need to consider other options such as a rack and pinion system, which isn’t something we have a design for. The second challenge is in shipping. The AltMill comes in three large boxes which can be shipped with a courier like UPS. A 4×8′ machine would need to have parts that are around 10′ long to make up the Y-axis, which would be heavier and harder to transport. This adds extra complexity in shipping and packing these parts safely.

That being said, we definitely see a strong interest for a 4×8′ machine. If you’re interested in one, please share your feedback in our Product or Feature Request Form.

Will there be a toolchanger available for the AltMill?

We do have a lot of people asking about this feature. With the SLB’s input and output suite and stronger Z-axis capabilities, the AltMill will be able to support a toolchanger in the future.

As in typical Sienci Labs fashion, we want to do a lot of testing and see if we can build something high-quality, reliable, and affordable, or work with another company to add this feature.

At this time, users will need to invest in retrofitting their own aftermarket toolchanger to the AltMill.

Can I buy the AltMill without the table legs?

Initially we were planning to have this a separate option, we’ve made the final decision to have the table legs a default part of the AltMill kit. There are two reasons for this.

Survey data about the table legs

First is that based on survey data from over 400 respondents, the majority said yes to wanting to order them. To save money overall, we decided that it would be most effective to design the packaging with the legs included.

This in theory leaves a small but not insignificant group of people who don’t want the table legs (24%), which is still a lot of people.

Back when we didn’t have a default router mount size (65mm) for the LongMill, a lot of people ordered the 80mm mount thinking that they were going to toss on a spindle instead. What happened in reality was that most of these people decided to not go down that route and just get the Makita router we’ve been recommending. Because these customers would need to order the 65mm after getting their machine with the 80mm mount, we found that it was just more cost-effective as a whole to make the 65mm the only option, and have the other mount sizes at an additional cost, especially if you took into account the extra customer service, shipping, packaging complexity, returns processing, and time wasted.

I feel like the table legs may follow a similar story because designing and making an AltMill bench will probably cost a lot more time and money than slapping on the ones we’ve made. I believe if we make the legs optional, there will be a lot of people who don’t order the legs at the beginning, realize this fact, and then have to spend the extra shipping cost to get a set of legs sent to them.

For someone who truly doesn’t need the legs, yes they may go to waste. However, in the grand scheme of things, making the legs defacto makes the overall cost to the customer lower.

AltMill Launch and Production Schedule

Hey everyone, we’re excited to share our launch date for the AltMill.

The AltMill will launch on Wednesday, March 27, 2024 at noon, EST. You can access the order page at https://sienci.com/product/altmill/ when the page goes live.

Our livestream will be happening on the same day at 1PM EST. Please join us at https://www.youtube.com/watch?v=QufxkgPRxCU

If you’d like to learn about the AltMill itself and the engineering behind it, please read our Everything You Need to Know about the AltMill article.

For more information about the AltMill project, please see https://sienci.com/altmill/. If you have any questions about the AltMill, please see the FAQ.


The AltMill will come at a base price of $2950USD/$3990CAD, which includes the table legs.

Users can also purchase the Spindle and Dust Shoe Kit for an additional $515USD/$690CAD.

The first 50 machines

As noted in past updates, we’ve jumpstarted the process by starting production on the first 50 AltMills in December 2023. This allowed us to tackle some of the major unknowns/questions, such as:

  • What will it cost for us to make the AltMill?
  • How difficult will it be to manufacture certain critical parts, such as the rails, linear motion, and table that we were most concerned about?
  • What will our QA and assembly process look like?
  • What sort of performance and reliability should we expect from the AltMill.

As of the time of writing, the plan is to offer the first 50 machines directly to select users and for internal use before our “main batch”. The first batch of AltMills represents our trial-run for production and comes with a couple of you-should-knows, especially if you’re planning to be one of the users in this batch.

We also plan to collect comments and feedback from our first batch of AltMill users to improve the user experience and tackle any initial quirks and issues in the first part of the product launch.

Some parts are still in shipping and manufacturing, and we expect the first 50 machines to start shipping in May 2024.

The “main” batch

This is what we expect most users will be part of. We will begin taking pre-orders at the end of March. Please check www.sienci.com/altmill for more information and a link to the order page.

The goal for our first main batch is to build enough units to leverage economies of scale to make our relatively low price for the AltMill viable. This not only involves the unit cost of the machine, but the work and labour needed to build each batch of machines, which might include work done to set up tooling, packing stations, and the ordering of parts.

Please note that to place your order for the AltMill, the total amount must be paid to hold your place in our queue.* You may cancel your order at any time before your order ships for a full refund. Once your order is in the possession by the courier or arrives at your door, our standard store policies apply.

The number of machines we’ll make in the first batch is still undetermined and will be based on the number of orders we get at the beginning of the launch. 

We expect the “main” batch to start shipping in July 2024. However, we will ship orders based on when they were placed, which means that if your machine is in the later part of the batch, you will receive your order accordingly after July 2024.

Future production

If you feel that pre-ordering the AltMill now isn’t right for you, you will eventually be able to order and have an AltMill ship to you in a shorter amount of time, just like the LongMill. However, when this will happen is dependent on when our production capacity can meet the demand for the product, which is unknown at this point.

The goals for the future production of the AltMill is as follows:

  • Have a reasonable lead time for us to build and ship AltMills. For us, two weeks or less from when we recieve an order to when it gets shipped is a pretty good number to hit, but the lower the lead time the better.
  • Produce larger numbers of machines to leverage economies of scale and either reduce the price of the AltMill or invest our increased profits into additional resource development and R&D that benefits the CNC industry
  • Take our learnings from this new product, especially in the production and QA side to create variations to the AltMill, such as a smaller, stouter, more rigid machine focused more on metal milling, or a larger 4×8 machine.

The size of future batches will be adjusted based on demand once our main batch has completed.

How to get updates

We will continue to share and provide updates in our Production Updates which are released at the start of each month at www.sienci.com/blog

Additionally, we will write order updates as we currently do with our other products at www.sienci.com/order-status

For the most reliable way to get news and updates, please sign up for our email mailing list.

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Get Your LaserBeam Vortex Riser Mount – Available for Purchase Now!  

The LaserBeam Vortex Riser mount is now available for purchase! It is a new add-on made for pairing with the Vortex. The Riser mount increases the z-axis height of your laser, providing significantly more room for LaserBeam focusing. Additionally, the product allows for more variation in LaserBeam mounting positions and is compatible with all versions of the Longmill router mounts.  Made of premium zinc-coated steel, this rigid and durable mount is the perfect addition to take your rotary laser engraving to the next level.

LaserBeam Vortex Riser Mount

(4 customer reviews)

This mount raises the Z height of your LaserBeam so you have more room to focus the lens. Each LaserBeam Vortex Mount order includes: 1 Zinc coated steel mount 5 M3-10 screws This product uses both the Laserbeam and Vortex systems. For more information on this product, you can view our resources here https://resources.sienci.com/view/lb-manual-vortex-riser-mount/ and…

274 in stock

Category: ,

We’ve prepared a detailed resource page and a video on assembling and attaching the Vortex Riser Mount to your LongMill. Also,  feel free to check out the additional update to the LaserBeam resources that details how to use offsets in g-sender with the Vortex Riser Mount and a variety of different Sienci mounts. 

If you’re interested in learning more about the LaserBeam and Vortex Riser mount, visit our product page below.

SuperLongBoard Pre-orders to Launch Dec 4, 2023

Hey everyone. We’re excited to share that the SLB will be launching on Dec 4, 2023. Chris and our development team have been going full bore in bug fixing, testing, and doing the final prep to get the SLB ready for production.

For the pre-order page, please visit https://sienci.com/product/slb/

There are simply too many features and updates to share in one blog post, but we do have lots of different content and information you can check out to find out more about the SLB on the Youtube video, the product page, and our blog article, Next Big SLB Update .

Putting the AltMill Project Back on the Burner

Hey everyone. As you guys might have seen in the November update, we are now back working on the AltMill. If you have been following along with us since 2021, you might have heard about the AltMill project.

From 2021 and 2022, there were a couple of reasons and factors that led to us putting the AltMill project on the back burner, which included:

  • Not having enough space for the development and production of the machine in our current space
  • Continued need for development and focus on the current LongMill product
  • A general decision to focus on the lower end/hobby of the market at the time

However, in 2023, we’ve now established a strong process for the LongMill and with the move to the larger building, we feel like it’s a good time to put the AltMill project on the front burner again.

Things are already moving forward with the AltMill, as we currently have 50 machines in production for our first batch. We expect parts to start arriving for assembly in the next 2 months.

What is the AltMill?


The AltMill is a CNC router that uses ball screws and linear guides and has a 4ft x 4ft working area. This addresses the two big “asks” we get from the LongMill community for a new machine, which is to:

  • Having a larger working area
  • Getting rid of v-wheels

The AltMill focuses on the same core ideas as the LongMill, which is:

  • Be simple, affordable, and easy to maintain
  • Come with excellent support
  • Be beginner friendly

The AltMill is aimed towards:

  • LongMill users who want to upgrade to a faster, larger, and more powerful machine
  • Hobbyist, prosumer, and small business owners who want to use for small scale production work

The AltMill is a completely new machine, with basically no parts shared between the LongMill, but users will find the process of running the machine to be almost identical.


  • 10,000mm/min rapids with closed-loop stepper motors
  • Higher rigidity with HG15 linear guides on all axis
  • Higher precision with 16mm ball screws on the X and Y, and 12mm ball screw on the Z axis
  • A working area of approximately 50″ x 50″ on the X and Y, and Z travel of approximately 6.5″ (with 4-5″ Z-clearance under gantry)

Changes to the original design

The fundamental structure, layout, and size of the AltMill between the original one we designed (More info here: https://sienci.com/2021/10/15/altmill-and-longmill-survey-results-and-development-progress/) and the one currently in production is with the linear guide choice and the frame.

The original design used SBR16-type linear guides, which had a few advantages, with the primary one being that the height that the linear guide blocks sat met up with the exact same height as the ball screw nut, making it possible to mount everyone on the same plane like shown in the picture below. In this design, we mounted everything to machined plates.

We initially avoided using “square rail” guides because of their cost and need for more careful assembly, but with our new experience working with different manufacturing techniques and other factors such as finding a well-priced supplier for the components, using rails such as the HG15 family of parts became viable.

HGH15 components

One of the main manufacturing techniques we’ve come to understand better and use is extrusions. We’ve used this technique for making the LongMill rails, LaserBeam heatsinks, and the t-track clamping system, so we now have a better understanding of the tolerances we can achieve, and because extrusion allows us to space the components as we want to, we’re able to make more rigid structures while keeping the whole machine lighter. Additionally, we can add extra features to the rail and position components where we want.

Adding features like t-slot and locations on the ends to tap holes, we are able to reduce the number of parts needed and provide more freedom in mounting different things to the machine.

We use three main extrusions in the X, Y, and crossbracing of the table that keep the machine rigid while reducing the number of parts needed to put it together.


Switching to an extrusion-based design also helps drastically to increase machine rigidity, without increasing weight. In the LongMill MK2, we were able to increase the rigidity of the X-axis beam while simultaneously decreasing moving mass by switching from a solid ‘open channel’ angle aluminum profile to a ‘closed channel’ extrusion. This makes for a significant strength-to-weight ratio improvement, which has been the case of the AltMill’s latest design revision as well.

This is especially relevant for the case of the X-axis beam in most CNC routers, since tend to deal with very high torsion loads; twisting the beam. Closed channels (tube structures) are the most optimal shape for dealing with these loads, the closer a profile gets to becoming a perfectly round tube structure, the better it is at handling this load, and the better our machine will perform.

Simulation of an X-axis extrusion profile iteration, stress concentrations shown on right

The new AltMill’s X-axis extrusion has also been sized to be much more robust than the LongMill’s X-axis extrusion. With better linear motion components, faster cutting speeds, and more utilization of higher-powered spindles it’s important to rebalance different components of the machine to ensure there are no weak points.

The rigidity coefficients of the AltMill’s X-axis extrusion at various wall thicknesses, compared to some other extrusions

In a CNC router, you generally want to balance any deflection across all components evenly. Having a very rigid machine with a single weak component that causes it to perform poorly usually doesn’t make sense from an engineering or practical standpoint. Looking at a breakdown of various sources of deflection on the LongMill, we can see that with the exception of the V-wheels, the LongMill does a pretty good job of balancing this across major parts and sub-systems.

Since we’re now removing V-wheels from the equation in the AltMill, we now look towards some of the largest areas of deflection, since these will make up the bulk of deflection. Some of the more trivial areas such as the router mount, and deflection from the Z-axis linear bearings (MGN12 pitch deflection) can be addressed by better component selection, but the X-rail deflection stands out as an area where improvement will be needed at the design side.

Another, unrelated takeaway from looking at these charts is the variance of how much deflection the V-wheels on the X-axis contribute depending on their tuning and wear state. This can be problematic when you’ve set up your cutting parameters to fully utilize the rigidity of the LongMill (or any V-wheel machine), only to have them wear or fall out of tuning causing your rigidity to decrease and affect the quality of your project.

This isn’t to say that V-wheels aren’t more than adequate for the purposes of a hobby CNC router, but this matter becomes more of a concern when dealing with much more strenuous, repetitive projects where consistency over a long period of time is needed.

LongMill MK2 deflection breakdown by component/system

Another change not specific to the new design of the AltMill is the decision to pursue a closed-loop stepper motor system.

With regular stepper motors, the motor driver will instruct the motor to move some amount, and the controller will assume the motor has moved by that amount. If there’s nothing wrong with your machine, and you’re not running into anything that’s stopping your motor from moving, this almost always works fine.

When your motor driver instructs your motor to move some amount and it fails to move, or does not move the exact amount as requested, things get out of sync. This scenario is generally referred to as ‘losing steps’ since your stepper motor has skipped moving a few steps/increments and is not where it should be, or where the controller thinks it is. This is bad for a couple reasons such as:

  • The next toolpath your machine makes won’t be where it should be, typically meaning your cutting paths will appear ‘shifted’ in some direction
  • On a ‘moving gantry’ machine with two Y-axis motors, if one motor skips/loses steps, your X-axis will no longer be square with the Y-axis, and in serious cases you may damage parts or induce excess wear running it like this.
  • If the motors are unpowered (such as between jobs), bumping into the machine, or pulling one the router/spindle may move the motors causing them to lose position and create ‘shifts’ in your project the next time you run it.

Unlike a regular stepper motor, a closed-loop stepper motor will keep track of it’s position using a sensor known as an encoder. The sensor typically relays this position information back to the motor driver (ergo, closing the loop), to let it know if everything is in sync and motor is where it’s expected to be, or if something has gone wrong.

If something is off, the motor driver will correct for the difference, and move the motor’s position to wherever it should be. If it’s unable to, such as in the case of running into one of the travel limits, the motor driver will send an alarm signal to the controller to let it know that something has gone wrong, in order to salvage the project and prevent any sort of serious machine damage.

Closed-loop stepper motors also have some other neat benefits such as:

  • The ability to run at high speeds with reliability
  • More efficient operation (and resultantly with less heat)
  • In some cases, quieter operation

There have been a number of advances to hobby CNC technology and industrial technology in general that have made closed-loop steppers more affordable and easier to use. We’re excited to bring some of the new hardware into our designs.


We expect the base price for the AltMill to start at $3600CAD/$2650USD, which comes with the mechanics, hardware, and electronics. This price does not include a spindle or router, but we anticipate that we’ll have something available at the time of shipping that would be suitable for the AltMill, such as a spindle package or our Sienci Router that is currently in development for around ($250 to 800CAD).

Because the AltMill uses a frame structure to ensure the whole machine is level and square, we are planning to have specially-made table legs that can be added to the machine to allow the AltMill to be its own standalone bench, eliminating the need for users to need to build a bench like the LongMill. We expect this addition to come as a kit for around $150-300.

Other accessories (and necessities) such as T-tracks and dust shoes will be available specific to the AltMill near the time of launch as well. Most accessories that currently exist for the LongMill system of CNC routers will be compatible – this includes things like the LaserBeam, Vortex Rotary Axis, and any of the future add-ons that pair with the upcoming SuperLongBoard controller.

Users will need to provide a wasteboard (3/4″ MDF) to be mounted on top of the machine.


The AltMill is already in production and we expect the first batch of parts to arrive at the end of December. We expect to have our first working machine in February. We are ordering enough parts to build 55 AltMills and expect to yield a minimum of 50 units in this batch. We expect to have units start shipping in March or April.

50 units is a pretty small batch to start with at our scale, but since we’re not sure how much demand we’ll see for the product, we’ve decided to keep the number pretty low. I think even if we only sold 50 machines, since they are fairly simple and use a lot of off-the-shelf parts, we can keep them supported on a small scale as well. My expectation in the long run however is to be able to ship and sell around 1000-2000 AltMills per year.


We expect to start pre-orders sooner or later based on the demand for this machine. Basically…

  1. If people want to give us their money right away and pre-order now, we will set things up so that can happen. This would be the ideal situation since it would be less risky to invest in this new product for us financially, but be the most uncertain for the customer on when they would be getting their machines.
  2. We launch the pre-order when we have a fully working machine so that people can see what it looks like and have more confidence in a specific launch date.
  3. We start to sell and ship once we get all of the parts in and the design is complete. There would be a short wait time as we build and pack machines.

Let us know what you think. If you’re interested in ordering an AltMill now, please fill out the survey below.


Technically not an FAQ, but more of an anticipated FAQ…

  • Will the AltMill be compatible with a spindle?

Yes, we actually believe most customers will want to default to a spindle to take advantage of the AltMill’s higher speed and rigidity. We will be working on a spindle or higher-powered router option at the time of shipping that will be able to be used with the AltMill.

  • Can I upgrade my LongMill to an AltMill?

No. Because this is a completely redesigned machine, there will be little to no parts shared between the two platforms.

  • I want to pre-order an AltMill right away. Do I need to put down a deposit?

At the current time, we are planning to ask customers to pay the full price of the machine upfront once we decide to open up pre-orders. You may change or cancel your order at any time before your machine ships.

  • Do I need to assemble the AltMill?

The major parts of the AltMill such as the X-axis rail and Y-axis rails will come pre-assembled, but will have some basic assembly to help keep shipping costs low. We expect set up for an AltMill to take around 2-4 hours with a basic set of tools.

  • Will there be a 4×8 AltMill?

At this time, and for the near future we will only be offering a 4×4 AltMill. It’s possible we may look into creating a 4×8 variant of the AltMill much later on.

  • Will there be an ATC (auto tool change) spindle/system for the AltMill?

It’s not in our immediate plans to offer an ATC system for the AltMill, however, this is something that could be possible much later on as we continue development on the Sienci Router project. In the short term, it will likely be possible to integrate such a system on your own since the AltMill’s controller will run grblHAL firmware which supports more advanced tool-changing features needed for these systems to function.

  • Will I need to connect a computer to control the AltMill?

The short answer is, yes. The AltMill will need to be tethered to a computer at the time of launch. That being said, some of the development to move the computer onto the board or for us to provide a separate computer module applies that we’re working on with the SuperLongBoard for the LongMill, so we expect at some point, we’ll have a more integrated system for the AltMill. Currently the options we are assessing are expected to cost around $200-300.

LongMill Maintenence Wrench Improvements

Hey everyone! We have a small change we’ve made to one of the key components to the LongMill that we’ll start shipping for machines going out in the next few weeks.

For the uninitiated, every LongMill comes with a “Maintenence Wrench”. We include this in every LongMill kit as a tool for assembling the machine and adjusting things like the ACME locking nuts and eccentric nuts. Every LongMill comes with a wrench and a set of Allen keys for assembling the machine.

Functionally, the new wrench remains the same but with the biggest difference being:

  • Adapted to fit new ACME locking nut hardware
  • More ergonomic shape
  • And most importantly… a bottle opener!

We hope that small improvements like this make a big difference in your enjoyment of the LongMill.

Also, it looks like the hanging hole got missed…but should still be functional the way it is, but we’ll have to fix that in the next batch.

New wrench on the left, old (V1) one on the right. V2 not shown

Next Big SLB Update

It’s SuperLongBoard update time!

Hi everyone, Chris here. It’s great to be speaking with y’all again, it’s not often I get around to writing blog posts since I tend to be more behind the curtain on the tech development we do here at Sienci. As Andy mentioned in his November Production Update post, there’s a lot to update on so I’ll spread as many juicy details as I can. We’re now at over 400 people interested in buying the new SLB system we’ve been working very hard at so thank you for your support! It’s very clear that our community is very excited about this massive upgrade to the LongMill and for the future of the hobby CNC industry.

To read past updates about the SLB, see our first major blog post (First look at the SuperLongBoard) as well as all the Production Updates that Andy has been putting out to keep you guys updated on our progress: May Update 1, Aug Update 2, Sept Update 3, Oct Update 4.

There’s also a video I filmed which you can feel free to watch if you prefer to see more of my face 🙂


Let’s start with a quick refresher about how the SLB came to be Sienci’s biggest project to-date.

As many of you know, Sienci Labs has historically been built up by our mechanical solutions – an expected direction seeing as myself and Andy co-founded the company while studying Mechanical Engineering. Our goal with Sienci was always to take advanced, industry technology and try to find a way to simplify it in ways that made it less expensive and easier to use so that everyone could have access to making complex things at home. We feel like that goal of price-point and ease-of-access is something we’ve been proud and successful at to-date with our big projects like the LongMill turned LongMill MK2 CNC, LaserBeam laser system, Vortex rotary axis, AutoZero touch plate, and our unique MK2 Magnetic Dust Shoe.

What’s been clear to us since the start though is that the CNC experience won’t be able to be improved with mechanics alone. Most hobby CNC communities have quirks with their machines, but once those quirks are understood the majority of confusion comes from everything else you see day-to-day when you use it: designing projects, tool selection, feeds and speeds, machine control, and reliable cutting. This is why we started working hard on non-mechanical solutions that we’re also very proud of like gSender for open-source CNC control, our in-house feeds and speeds charts, our expansive resources for learning and understanding CNC, ever-growing roster of tutorial videos, and now the SLB.

Why the SLB?

The SuperLongBoard is a next-generation CNC control board we’ve been dreaming of making for years now and is getting closer to completion. We believe that at this current stage, integrating smarter, more reliable, and more capable CNC control electronics will make the biggest improvement to the CNC experience. If you look at options on the market there’s been a large divide between the capabilities and reliability of the typical hobby CNC boards in the $40-$200 price range and the far more expensive, semi-industrial options that can reach the several-hundred-dollar range to over $1000. With chips getting more powerful and lower cost, we thought that gap in ability could be reduced while still staying in the lower price range by making a board with those new technologies. We knew this was going to be a big challenge – there are reasons why it’s typically easier to up-sell older technologies than it is to develop new ones – but we felt strongly in our decision. We felt that creating a new, improved, and unique solution could bring new innovation to the market to benefit everyone by reducing barriers to entry, keeping the industry progressing, and making more reliable and capable CNCs at lower price-points.

Working alongside Andrew and his team at Expatria Technologies, and building off of Terje Io’s amazing grblHAL project, all these tools need to work hand-in-hand so we can set our sights on resolving two major areas that we think hobby CNCs could benefit from:

  1. Reliability: this is such a broad topic to solve, but it can be more-or less divided into a couple categories.
    • Board wiring and protections: designing a board with proper grounding and plenty of voltage protection and isolation takes a lot of time and experience but is needed to shelter the electronics from CNCing – an electrically ‘noisy’ environment from all the moving motors and static electricity buildup from cutting and vacuuming materials
    • USB protocol: this is implemented in firmware and grblHAL comes with far more checks with data communication mechanisms in place to guarantee delivery over USB and know when to resend lost information
    • Backup Communications: adding Ethernet on top of grblHAL’s already robust USB implementation isn’t necessary but having an alternate communication method to turn to is always a great option if you’re ever experiencing problems with the primary style – an onboard SD card also gives you that flexibility
    • Processor speed: a slower processor can’t buffer as much information when dealing with short and complex movements, meaning better chips can reduce the chance of errors popping up
  2. Room for growth & “Wow factor”
    • Motor drivers: the same stepper motor controlled by different motor drivers can see notably better performance with all else being equal – so why not upgrade to newer-age drivers to get better speed with less motor noise out of the same CNC
    • Smarter CNC: having the CNC better tell you when something has gone wrong, automatically fix a problem for you, or make one of your existing processes easier creates far less room for error
    • More control options: there are typically specific limitations on what a CNC can do, so why not expand it’s options to support all commonly used CNC accessories plus leave space for even more customizable outputs. This can include things like independent Macros buttons, independent Spindle and Laser control, Modbus over RS485 for more closed-loop VFD control, tool length sensor support, ring and rail lights, door sensor, CANBUS, CNC pendant options to control the machine more easily, adapting to plasma cutting, and more
    • Multi-axis control: benefits those who have started to dive into cutting rotary projects to create ornate, fully 3D projects on their CNC and want either a simpler transition between cutting styles or are interested in full 4-axis cutting
    • Onboard computer: if you’ve ever run into problems with a Windows update, USB port falling asleep, or having hardware too underpowered to run your CNC, these problems can all be solved with a dedicated, purpose-built, and built-in computing solution running something like gSender onboard

We think we can address most of these aspects with the SLB at the time it ships so it can play a part of the next big step in hobby CNC technology. It’s advanced electronics and software will bring not just new features and functionality to the LongMill, but at a price point that we believe will be affordable for hobbyists. With it being a Sienci project, it can also guarantee that the SLB will be backward compatible with ALL LONGMILL CNC MACHINES OF ALL GENERATIONS, which means that users can upgrade their machine’s capabilities by simply replacing the controller. It will also support all our current plug-in add-ons. We also plan, just like with gSender, to make our board well documented and able to be adapted to many other CNC form-factors when we start to work through rolling it out in production.

How it’s coming along

Very well! Since Andy’s last update, our SLB team has been working hard to prioritize checking the functionality of the physical circuitry on the V2 prototype board are we’re now feeling confident that the following circuity is good to go:

Newest version of the SLB (V2)
  • 24V 12.5A brick power supply input with power switch (no more power over computer USB)
  • External, detachable E-stop with light, controller feedback, plus 3 customizable buttons
  • More reliable implementation of serial communication over USB-C (no drivers needed) as well as Ethernet
  • 4 higher-end, independent motor drivers rated for 2.8A RMS (TMC2660C, higher efficiency, less noise and resonance)
  • RGB Machine status LED
  • ‘Contact’ style touch plate input
  • 4 independent limit switches with two connector styles and 5V or 24V output
  • Coolant digital output set via M8 and M9 commands (5V 40mA)
  • Independent rotary axis support with dedicated limit switch
  • Tool length sensor input for easier tool changes
  • Modbus over RS485 to control spindles and other accessories with two connector styles, terminal breakout and CAT3 cable with RJ11-6C/RJ25 and supports daisy-chaining
  • Very dust resilient enclosure with quick assembly
  • Many status LEDs for troubleshooting
  • Tons of opto-coupling for optimal protection against incorrect wiring and electrical noise
  • Less heavy boards with less fragile components should lead to lower failure rate
  • Extendable RGB LED ring light and rail strip output
  • 4 customizable outputs to external circuits, controllable via M62/64/63/65, M7/M9, M8/M9, and M3/M5 (2 SSR pin shorting and 2 relay/solenoid/motor driving)
  • SD card to store onboard information and possible g-code file overflow (min 512MB)
  • Door sensor for input to pause cutting
  • Special CANBUS for pendant communication
  • Extra breakout IO to access spare MCU pins and other alternate outputs
  • ADC input for future sensor input
  • Communication connections (e.g. Rx and Tx) available for future control via external controller / pendant

These could still change a little on our way to production but I’m very confident that this will give an accurate image of what the SLB will be capable of. The gray items on the list might not be ready at the time of launch but the great news is that we have verified all their circuitry and put them on the board so all that’d be missing is a firmware update we plan to put out after shipping boards to enable those features as well.

The main items absent from the list are twofold:

  1. Firstly, though we aimed for the V2 board to be our second and last prototype, we did find some areas that we wanted to tweak. These were: changing the Spindle 0-10V output back to 5V PWM to support the new spindle we’re working on, changing the Laser PWM and Flood output circuitry to deliver a signal that’s more in-line with the previous LongBoard, tweaking the RGB LED driver buffer, fixing some onboard status LEDs that were floating, and adding some more EMI improvements. Most of these changes are quite small, but we decided that getting a V3 prototype made will help us feel confident in finalizing the design for production. This is a hard decision as it’s likely going to add another 1 month to our board release timeline, but we really wanted to be sure to support one of the key features we wanted the board to have “Independant 5V PWM and EN Spindle and Laser control set via M3, M4, M5, and S g-code commands, plus SpinDir“. The V3 design should be sent out to get made in the next week and should now lock-down the full SLB design. While we wait for it to arrive we’ll be focusing fully on testing and firmware improvements.
  2. Secondly, for those who might not have been following Andy’s production updates, we’d originally envisioned the SLB as being a system of two different parts working together. The first being the board itself, containing all of the core CNC functionality controlling motors and handling g-code, and second being an optional onboard compute module that would act to replace a computer or laptop and instead be integrated. Users could connect a keyboard, mouse, and monitor to control all functions of the machine directly through the SLB. This was very exciting to us given the considerably low price of the compute module over a computer, around $40-80 dollars plus the cost of the monitor, keyboard, and mouse, as well as the extra speed, user experience, and reliability of an onboard system.

    In our extended tests with this idea in mind, we weren’t finding the success we’d hoped in creating a seamless user experience with this solution. Despite trying many Linux kernels, drivers, GPU acceleration, and bringing many more efficiencies to gSender, the Broadcom and Rockwell-based processors used on smaller compute modules were not powerful enough to accommodate the visualization of g-code directly onboard. This also meant they didn’t have extra headroom if in the future we wanted to implement other features such as having a camera monitoring system or other sensor inputs. With many months delay trying to chip away at a resolution we decided to split the development of SLB back into its two parts; prioritize improving the baseline machine performance first so CNCers don’t have to wait any longer for the SLB to make better machines, and strip out all the on-board connectors and switch to a higher-power off-board solution that we’ll implement at a later stage. This will mean anyone could still upgrade at a later date. Higher-power Fanless PCs will cost more, from our initial budget of around $80CAD/60USD for the compute module, to somewhere around $100-$200USD depending on the specs and configuration, but would ensure a smooth and seamless experience as well as provide headroom for future applications.

    To summarize, we decided to take the concept of the onboard computer and divide and conquer on it at a later date. It would’ve been really cool to have a fully integrated system but it kept pushing our board delivery back further and we felt it would benefit everyone if we just pushed ahead on the other features that will all still bring great benefit to the CNC experience. This means that users will still need to connect their computers to the board to control their machines when the first batch of SLBs release, but should still see drastic improvement.

To-date, SLB development costs have tallied to more than $300k, making it easily our most expensive project to-date if you don’t count gSender which is I’d guess is around $500k at this point. These costs are pretty standard and have mostly come from paying salaries to do in-depth research on board infrastructure options, decisions on features that CNCers would like, designing robust PCBs, lots of custom firmware development, and testing. The new board uses a large number of components, adding to the challenge and complexity in manufacturing, but this was expected and we’re working through it. We feel confident that we’ve done something useful here and we’re excited to see the interest in the SLB on launch and continue moving development forward.

grblHAL support in gSender

Another big effort we’re having to undertake to support the SLB has been with gSender. Though grblHAL has “grbl” in the name, it might as well be a completely new firmware with all the new work that our development team has had to put in so far to make a seamless CNC control experience and UI. Since grblHAL is such a new firmware on the hobby CNC scene, it’s still growing and not widely adapted, and we want to help change that. There’s so much documentation that has already been made but there’s also a lot more we have to figure out. We’ve been working on an all-new firmware flashing utility for the new board, and had to build in a lot of modularity so gSender can be compatible with old and new boards alike

Look at an example of all these new EEPROM settings!

You can see this progress being made live, with each new gSender Edge version we’ve been releasing since the start of this year.


Iteration on the SLB enclosure I think is coming along well, the design is now pretty much locked in 🙂

Back in April I put out a post on our Forum with the leading design we had at the time to get peoples feedback on what they thought (https://forum.sienci.com/t/official-call-for-feedback-on-new-board-in-development/8519) and the results were positive but still mixed. I wanted to take a new approach to the enclosure design to accommodate all the new plugs without them all being exposed, as well as improve cable management on the LongMill in particular. Though many people were on board, many still expressed concern with my idea behind mounting the board to the Y-axis rail due to their fear of dust, vibration, or accommodating enclosures.

After going through way more iterations internally, this is now our revised design which I feel much more confident will suit everyone’s needs:


The main perks of this enclosure is it’s mounting versatility and wire management. With this new setup, anything that you’d expect to have more common access to faces toward the front and all other wires can be routed out the rear. The RGB status LED will be visible through the faceplate put the panel will also be easily removable for troubleshooting or servicing. All the components on the board face upwards so everything is accessible and the board has been tested to run very cool so even in hot environments and with the bit of venting we’ve added in we expect everything to operate as normal.

Rail mounting bracket

The rail mounting is also a separate piece that can be used or not. This gives versatility to mount the SLB on any surface (rail, vertical, or horizontal) with 2 or 4 screws. We’ve already begun production of the parts and should be getting them in Nov-Dec.

E-stop Design

This is also mostly completed, just waiting for some last few checks. You’ll notice on the earlier feature list that we wanted to move away from the 3 buttons attached directly to our board. This is because there was feedback that people didn’t tend to use the existing buttons because of their fixed function, and when people mounted their board out of the way they couldn’t access the buttons anyway. We wanted to fix this by making the buttons separate and customizable, and this lead to a new E-stop design with 3 other customizable buttons integrated into it! Now you’ll have the freedom to have 3 physical buttons perform a myriad of custom functions to suit your workflow right next to your E-stop.

New E-stop design

Beta Testing progress

As we’re turning the corner on finalizing the board design and implementing our initial set of firmware features, our main goal over the next month will be: test, test, test! We’re now in Phase 2 of Beta testing where our main goal is to make sure that all our new features play nicely with each other, since we already know they work well in isolation.

We currently have 3 boards with testers and 2 dedicated machines in our own shop running CNC jobs every chance we can get and have already found unique situations that cause problems which we can now work toward resolving. This also involves comparisons between the old and new board and real-life durability and performance testing. One example is Ian’s Onefinity where his former setup used our original Longboard and with the SLB he’s seen drastically reduced noise and nearly doubled movement speeds. This hasn’t been as drastic for our other testers but we’re also already noticing some of the stability and perks that the SLB has to offer. Once the batch of V3 boards arrive, the plan will be to redistribute them as well as contact a new wave of testers to complete one final round of feedback. Some people we reach out to will be those with persistent and existing EMI and disconnection problems to see if the SLB is able to resolve those issues. At that point we expect to feel confident in the performance and features we can promise with the board that we can prepare for release.

Here’s a video from Andy’s last post of us testing the new programmable macro buttons. These allow you to program a specific code or function to 3 unique buttons, rather than just start, pause, and stop, which is hardwired into the current control board. In this case, it’s being used to move the machine to a specific position to assist with getting the machine out of the way for changing tools and materials.

Pricing and Timeline

If you’re interested in our previous evaluation on price, you can look back to Andy’s original big post under the “Pricing” header (https://sienci.com/2023/04/10/first-look-at-the-superlongboard/).

The pricing is likely to be refined as we’ve made new decisions and near production, but I think no matter how you slice it you’ll be able to expect that the SuperLongBoard will be giving you every bang for your buck.

As far as timeline, many followers of this project would know that we’ve had to push our originally anticipated late-summer, early-fall launch. We’ll be putting out another update soon on the roll-out strategy we have in mind moving forward because we want to give people a guarantee to be in line for the SLB before Christmas, so stay tuned to hear more about that. You can get a glimpse of what some of the steps will be with the roll-out in Andy’s original post as well under “What’s Next?”.

As far as ongoing project schedule, much of it has been laid out in the sections above which I’ll try to summarize here:

  • Last tweaks will be made in the next week to start a batch of V3 SLB prototypes
  • Firmware, Beta testing, and gSender support will continue over the coming month while we wait for the V3s to arrive
  • SLB Enclosure and E-stop designs should also become finalized and be ready for production in the next month or so
  • Once V3s arrive, final checks can be made to feel confident about the circuit design and begin board production
  • Phase 3 of Beta testing will continue to refine Firmware and gSender support while all other production is underway

I’d say that this means the boards won’t be ready to ship in December / Christmas and are instead more likely to be able to ship around Feb-March. The first major steps we took until June 2023 involved much of the initial product churn that we expected to see, though with delays in board prototypes and unexpected difficulty interfacing with the drivers we lost about 2 additional months. Add to that the outcome of the compute module testing meant that we had to pull out a lot of components for a full redesign between V1 and V2 and now we have to address some of the missed items between V2 and V3. This is the reality of developing such a complex product and is why we now feel much more confident with the recent testing and steps that we’ve taken that the completion of the SLB for launch is just around the corner 😀


Thanks for sticking along for the ride on this big update, I hope it answers most of your questions on where the SLB is currently at and gets you excited about what’s to come. I expect the SLB to be very unique in it’s abilities to exceed the capabilities of many hobby CNC boards, perfect even for the DIY hobby CNCer for all it’s additional IO, and still have many more plans for it in the future. Of course it’ll be an Open-source design so hopefully all this time and effort that our team has put in will be able to return to the community and benefit other efforts toward easier CNCs.

Leave any comments you have that I missed and I’ll try to answer them. As I mentioned I don’t tend to put out updates because I’m a very slow writer but I’ll ensure to keep Andy in the loop as progress continues so he can update y’all as things keep moving forward. Just remember to read the Production Updates!

Catch ya later

Everything you need to know about the spring-loaded anti-backlash nut

Hi everyone, I’m excited to share a small development, the Spring Loaded Anti-Backlash Nut! As we’ve continued to have LongMills out in the wild, we’ve recognized that the finickiness of the Delrin Anti-Backlash Nut was a pain point for our users, such as the need for adjustment on a regular basis, the potential for the adjustment screw to fall out, and improper tensioning causing jamming, especially at higher speeds.

The Spring Loaded Anti-Backlash Nut is designed to address these issues by using a set of springs to tension the nut against the threads radially, allowing smoother operation and no adjustment needed from the operator. We are now putting this out into the wild for field testing!

These nuts are drop-in replacements for any T8 size Delrin nut on the MK1 or MK2 LongMill.

Assembled Spring Loaded Nut

This new version is now available on sale and ready to ship in our store.

Flaws with the current Delrin Anti-Backlash Nut

For those who don’t know, the Delrin Anti-Backlash Nut design comes from the original Openbuilds Anti-Backlash Nut Block. At the time, this was more or less the best option for this type of hobby CNCing for T8 lead screws because it’s:

  • Inexpensive
  • Simple
  • Easy to manufacture
  • Easy to integrate
  • Low maintenance
  • Generally works pretty well

Since we were still in the early stages and didn’t have the manufacturing volume and capability to make our own designs at scale, we stuck to a lot of open-source and off-the-shelf components. As some users may have noticed, we’ve slowly been working on different innovations to improve and redevelop our own components to work better and more reliably.

The original design comes with a couple of flaws:

  • Requires constant adjustment to reduce backlash
  • Over-adjustment or incorrect assembly results in binding
  • Inconsistent resistance during its life cycle

To improve on this design, I worked on some different concepts using springs to pre-load the nuts, finally resulting in this shape:

“This design incorporates OpenBuilds, LLC design work(s) shared Open Source under the CC BY-SA 4.0 License.”  

In this design, we use two springs in the gaps to apply radial preload on the lead screw threads. This allows the two “arms” to push into the threads as it wears, automatically reducing the backlash.

According to Helix Linear, another manufacturer for anti-backlash nuts, “the radial anti-backlash nut can handle loads greater than the spring force. There is also less of an increase in required drive torque compared to an axial anti-backlash nut.”

In this design, we use two arms instead of three typically used in industrial nuts, to keep the same form factor, so that the new nut can drop in to replace the current version with no modification.

Other benefits include:

  • Zero adjustments or maintenance after installation
  • Lower potential for binding
  • Smoother, lower resistance operation

Next steps

We’ve done some initial testing with 3D-printed nylon nuts, which have pretty good results, showing basically no backlash over testing. We’ve now ordered 400pcs (100 sets) of machined Delrin nuts. Our goal is to put them available for sale for people to use on their own machines. If they work well in the field we will switch to spring-loaded nuts as the default standard in LongMill kits.

I should include a disclaimer, which is that these are still a new, unproven product, and it is still possible that in the long term they may perform worse than the original nut.

We want to put these nuts out in the field so that we can get feedback and long-term testing done to validate the design. I’m very confident that this will make an improvement to the overall experience of using the LongMill, but before we make the switch, we want to make sure that we do some real-life testing.

There may be some small tweaks we may consider making, such as adjusting the spring force and length and spacing of the arms, which may happen based on the beta testing.

For this first batch of nuts, we will collect some survey data to help understand the experience of the user. At this current stage, we only have T8-size nuts, but we may expand it to the T12 size as well.

August 2023 Production Updates

July was a bit of a slow month due to the Vancover port strike holding up shipments for us to ship LongMills in the queue. However, now that parts are back to arriving again, we’re picking back up with our regular routine.

We have a lot of news to cover, especially with the pending release and shipping of the Vortex Rotary axis and new development around the SuperLongBoard.

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UPS reaches labour deal with Teamsters before strike

This July, we found out that Teamsters working for UPS were preparing for a strike in August, which would have disrupted shipments going to the US. However, UPS and Teamsters have settled on a new UPS contract which increases worker wages across the board and improved working conditions.

We are happy to hear that a resolution has been made, especially as we get into the busiest part of the season for our business.

LongMill and Extension Kit Orders

July has been a slow month for us shipping out LongMills as we have been affected by the port strike that delayed our shipment of controller boards. However, I’m happy to announce that we will receive the boards today and expect to clear the queue in the next 2 weeks.

The large majority of the pending 100 LongMill orders have been packed and are waiting to have the controller boxes done to have them shipped out.

Some LongMills waiting to be shipped

As some folks may know, we’ve continued to work on smoothing out the process of dealing with customs for shipments going to the US. Recently, we’ve been assigned a single contact with UPS to handle all of our LongMill shipments that need customs clearance going to the US. We found that some items were being miscategorized for duties and taxes, and we suspect it is because a big part of this is a manual process that causes human error. We believe that having a single contact who is familiar with the line items will speed up the clearance process with fewer mistakes.

A few new design updates on the LongMill MK2 design include a focus on phasing out of using M3 bolts in the assembly process and replacing them with M5 screws, including parts such as the couplers and ACME locking nuts. We are phasing out components using M3 screws in the LongMill assembly process because they are prone to stripping the heads more easily. Eventually, a full LongMill will be able to be assembled with just one M5 Allen key and our special wrench that we provide (as well as a drill and bit to mount your LongMill to a wasteboard of course).

Some new prototypes of the assembly wrench for new hardware
New T8 locking nuts replacing the brass ACME nuts

We are also starting to use longer Z motor cables for the motors so that LongMill 48×30 kits, which are now the most popular variant, will not need a motor extension cable, simplifying the assembly process as well.

Additionally, now that the design of the LongMill MK2 has matured over the past year or so since its launch, we are moving to figure out injection molding parts for it for the first time. If you didn’t know, we 3D print several components for the LongMill MK2, including the dust shoe and feet. We found that due to the large number of feet we print, moving to injection molding would be a natural next step to reduce our need to rely on the 3D print farm, which is harder to scale production for.

We are entering into the first day of August with around 100 pending LongMill orders, but we expect to clear the queue in a week or two, after which we expect to shorten lead times again.

Vortex Rotary Axis

The last of the Vortex Rotary Axis parts have arrived at the end of July and we are now starting production and assembly!

First batch of machined parts looking beautiful
Test assembly of the Vortex kit
Switch assemblies for Y axis to rotary mode

Our team has been continuing to work on different areas of the Vortex so that when they get into the hands of our users, they’ll have everything they need to get started. This includes:

  • Thorough assembly and installation instructions. We just completed initial trials and tests of the assembly process to make sure that we provide clear instructions to make it easy to put together. We found that everything came together really easily, except for the cam clamping system for the t-track, which we are currently working on to make it less finicky. We estimate that most users should be able to put it together in about 30 minutes. Full instructions will be found on our Vortex Resources soon.
  • Video content about the Vortex. We understand that not a lot of how-to and tutorial content exists for rotary CNCing. Our video production team and the engineers are working on the next steps for creating content so that our users can learn how the Vortex works and how to use it.
  • The gSender team continues to work on completing Rotary Axis implementation into the gSender, including homing and visualization for rotary. These features will be in gSender Edge at the time of launch and will be merged into the main version of gSender down the line. You try and learn about the latest version of Edge here.

We will start to trickle out Vortex Rotary Axis kits over the next week or two as we iron out the last bits of details. We expect the first batch of kits to start shipping out at the end of this week or early next week.


LaserBeam production continues to move along smoothly, with most orders shipping out within a few days. We have stock available for the LaserBeam ready to ship now.


Work for the SuperLongBoard (SLB) continues on. The team has been able to successfully test the main functionality with excellent results. However, we found our initial tests with the onboard compute module to be unsuccessful, as the Broadcom and Rockwell-based processors used on smaller compute modules to not be powerful enough to accommodate the visualization of g-code directly onboard.

Revised SLB

While additional software development was able to make significant speed improvements, we felt that the compute module would most likely need more headroom in the future if we were to implement other features down the line such as having a camera monitoring system, which we felt would be difficult to add due to a limitation of system resources.

We have now started looking at higher power compute modules, single board computers, and other hardware that we feel would ensure that the onboard gSender experience would be smooth and seamless, as well as provide headroom for future applications. However, the downside is that higher-power computers also cost more, and while our initial budget was around $80CAD/60USD for the compute module, we expect the computers to cost somewhere around $100-$200USD depending on the specs and configuration.

That being said, since we don’t need to have certain components and other parts to support the onboard computer directly, some of the cost of the computer is offset by the lower cost of the SLB itself.

We’ve decided to split the development of the SLB into two parts, one for the board itself, which will use grblHAL, a new, more advanced firmware and all of the improved motor control and drivers, and the computer itself. This means that the computer will live off the board in one fashion or the other.

While it would have been really cool to have the whole system integrated, we believe that by dividing and conquering, we can have the main portion of the SuperLongBoard out of the development process and into production first, and focus on the computer addition after. We felt like we could tackle some of the main problems with the current LongBoard with the new controller, and that it would be better to have the improvements we’ve already developed reach users sooner rather than having everything wait on further development on the onboard computer side.

This means that users will still need to connect their computers to the board to control their machines when the first batch of SLBs release, but better communication protocols, electronics, and shielding will make the USB connection significantly more reliable than before. Andrew, our main developer on this project, assures me that unreliable connections that cause issues with some users with the current board will be a thing of the past.

This version of the SLB natively supports communication over Ethernet, as well will have onboard storage which allows for streaming onboard rather than through a cable, which will improve reliability as well.

We are making the final design changes to prepare this version of the SLB for prototype production, and we hope to have production boards available near the end of the year. If you want to learn more about the SLB, please read: https://sienci.com/2023/04/10/first-look-at-the-superlongboard/

Vortex Rotary Axis Launch Date – June 1, 2023

The Vortex Rotary Axis* will be available on June 1, 2023, at 1 PM Eastern Standard Time, where the first 300 units will be available for pre-order. We expect to ship in August 2023.

New videos and content coming out for the Vortex soon! Make sure to sign up for our mailing list, for new updates and other Sienci-related news. Subscribe to our Youtube channel where we’ll post more videos on the Vortex Rotary Axis in the new few weeks!

*After much debate, we have decided to call the name for this new add-on the Vortex Rotary Axis

It’s been a long journey for developing the Vortex Rotary Axis, but we’re finally excited to share a launch date for our new add-on! This new product aims to make doing rotary projects like making bats, wands, furniture legs, bowling pins, and other turn-able projects with your LongMill and the Vortex.

The Vortex is unique in that not only is it a compact, precise, high-quality rotary axis we designed from scratch, but our direct integration into gSender also plans to add functionality not found in other CNC systems. Additionally, just like all our products, the Vortex will be supported by our team with high-quality tutorials and resources to make it easy to install, learn, and use your rotary axis.

The Vortex can be integrated, plug and play, in any standard LongMill CNC**, and comes with the hardware, electronics, and instructions to help you find success with CNC rotary carving!

**With the exception of the 12×12 LongMill MK1. Integration for the Vortex Rotary Axis on 12×12 machines may require moderate modification to fit.

Video Content

What is a Rotary Axis?

The Vortex Rotary Axis is an add-on created to allow users to integrate a rotary axis into their LongMill.

Most CNC routers like the LongMill use a 3-axis system, which consists of an X, Y, and Z linear motion system that is used to position bits and end mills. One of the limitations of a 3-axis system is the fact that 3-axis machines cannot make “undercuts” without flipping or material manually. Since the machine only can orient the bit vertically, there are limitations to the types of geometry it can carve.

Source: https://waykenrm.com/blogs/undercut-machining-for-cnc-machined-parts/

To address these limitations, CNC machines can come with additional degrees of motion, typically including a 4th or even 5th axis. In the case of the LongMill, a rotary axis positioned along the X direction allows the machine to turn a part as the X and Z axis can move in sync as the material turns and rotates.

On a mechanical level, the 4th axis for the LongMill will come with a chuck to hold the material as well as a series of bearings and pulleys connected to a stepper motor to rotate the material as the machine carves. This allows for users to make projects like:

  • Bats
  • Chess pieces
  • Furniture legs
  • Wands
  • Figurines
  • Busts

and more!

Production and Pricing

Each Rotary Axis will come with all of the hardware and electronics to integrate the kit into any existing LongMill CNC.

The Rotary Axis will start at:

$600CAD/$449USD – For 12×30 and 30×30 LongMills

Dimensions below.

$640CAD/$469USD – For 48×30 LongMills

Dimensions below.

The main difference between the two options is the rail track extension that allows users to mill larger items corresponding with the X-travel range on each version of the LongMill.

All options will come with a standard jaw that can hold material in several configurations:

Additionally, customers should budget purchasing rotary axis ready CAM software, such as:

  • Vectric VCarve Desktop, VCarve Pro, and Aspire ($349USD, $699USD, $1995USD)*
  • Fusion 360 ($1600/year)
  • DeskProto Multi-Axis Edition (€249.00 for the hobbyist edition, €995.00 for commercial)

*Based on our testing, we strongly suggest Vectric software for its simplicity and user friendliness.

Resources and Support

It’s important for us to stress that the Vortext Rotary Axis follows our philosophy for providing a complete product, not just hardware, but high-quality support, resources, instructions, and tutorials to make sure users are able to use their rotary axis to the fullest.

We’ve recognized that not only are affordable rotary axis options are limited in the hobby CNC space, but the resources needed to learn it also are lacking. We’ve taken the initiative to provide support through the Vortex.

Did you know that we regularly post tutorials and educational content for the LongMill on our Youtube channel? Make sure to check it out and subscribe to us if you haven’t yet!

Production Timeline

The Rotary Axis is already in production, with parts expected to complete and arrive between June and July. We are expecting a late July to mid-August shipping date. Please note that because this is a pre-order, timelines may change due to delays and unexpected circumstances. We will continue to share production updates for the Rotary Axis on a regular basis on the blog here, so that customers can sign up for our mailing list, for new updates and other Sienci-related news.

Development Timeline

Mechanical and electrical design and development of the Vortex Rotary Axis is now complete, and we are currently waiting on production parts to complete and arrive. Our engineering team is currently working on stress testing and resource development, as well as preparing for assembly, QA, and packaging for the final product.

The software development team continues to finalize the development of the software support in gSender, such as implementing new features and getting testing feedback from users of gSender Edge. We expect basic functionality to be available at time of shipping, and we will continue to add more features in future releases of gSender.


When will the Rotary Axis ship?

Production on the Rotary Axis is currently ongoing, with the first units expected to ship in Late July to August 2023. For general development and production updates, please check our Blog. Orders will ship in the order in which they are placed.

What is the between the 48in and the 30in versions?

These lengths describe the track width for the rotary axis. Customers should purchase the size that matches with the working width of their LongMill.

When do you take payment?

We take the full payment immediately. Customers may cancel their order for a full refund anytime before their order ships.

What happens when all 300 units are sold out?

Based on early demand, we’ll decide on when we’ll start building a new batch. Turnaround times to build each batch takes about 3 months, so there may be a few months wait time additional once the first 300 units are sold out.

Will I get a notification or email before my order is ready?

Yes, we’ll send you an update email to let you know that your Rotary Axis is ready to ship.

Which machines is the Rotary Axis compatible with? 

The Rotary Axis is designed to be compatible with all versions of the LongMill, with the exception of the LongMill MK1 12×12, due to the track width (however it can be modified to work).

We will be providing full assembly resources for the Rotary Axis.

Although users may be able to integrate the Rotary into other hobby CNC machines, we will only be providing compatibility and support for LongMill users at this time.

How is the Rotary Axis driven?

In the current configuration, the Rotary Axis uses the X-axis and Z-axis to move along the rotational axis of the material, with the Y-axis drivers disconnected and reconnected to the Rotary Axis motor to provide rotational movement. This means that in this configuration, the system is not a full 4-axis machine, but more of a 2-axis + rotary system. Each kit will come with a switch to toggle 3-axis and rotary axis modes.

In the future, we are planning to provide full simultaneous 4th axis motion through the SuperLongBoard, expected to launch at the end of the year (at an added cost).

Does the Rotary Axis come with software?

We’ve implemented gSender to integrate the ability to control, set up, and home the Rotary Axis. Users will need to use or purchase CAM software that supports rotary carving. We recommend VCarve Desktop or VCarve Pro, as this is the software that we primarily use and do testing on.

Can I order other items alongside my Rotary Axis?

For logistical reasons, we strongly recommend users to place separate orders for the Rotary and other items. However, if you place an order for other items with the Rotary, we will ship them separately based on the stock availability of the items.

When your Rotary Axis is ready to ship, if you wish to order additional items to ship together with combined shipping, please Contact Us for assistance.

Some custom bats made on the Rotary