It’s been a short 10 months since we first launched the AltMill.

We’ve learned a lot with our first batches of the AltMill and we’ve combined all those things into improvements to our latest version. We’re now excited to share our second iteration of the MK2, which bring improvements to the quality, ease of construction, and quality of life, as well as preparing for new iterations and development for the Sm-AltMill and 4×8 machines in the future.

The MK2 refers to the platform change, which means that any machine with the new design changes are part of the MK2 family, which means that the AltMill 2×4 is also a MK2 machine.

If you’re looking for more information about the AltMill MK2 2×4, please check out this other blog post.

Production changes and challenges

AltMill lead times have continued to be long since the first launch of the machine. While our production rate has continued to increase over time, decreasing lead times have also coincided with increased demand, due to the growing public knowledge and interest of the AltMill. We are working on a number of things to decrease lead times and our goal is to eventually have units ready to ship in 1-2 weeks on average.

Batch sizes

To mitigate the risk of quality and technical issues in the shipping of our first batches, we’ve kept batch sizes relatively low, with Batch 1 being 50 units, Batch 2 being 200 units, and Batch 3 being 250 units. Batch 4, which we are currently in, is something of a split batch of 500 units. I am calling it a “split batch” because some components have been ordered and produced in a batch of 500 while some have been ordered in a batch of 250, based on cost, size, and our confidence in the part quality. Additionally, we’ve been working to diversify our supplier portfolio, so that we can split up parts from the same batch across two or more suppliers, allowing us to decrease lead times.

Supplier diversification

As our part complexity and quantity grow, we’ve worked to diversify our portfolio of producers and manufacturers. The first is to distribute work to decrease lead times. By using more than one manufacturer to produce the same component, we can ensure that if one manufacturer has issues or is delayed, we still have a second source for the products. Plus, if parts take a long time to make, having a smaller batch to produce can reduce the total production time.

Second, we’ve been working with different manufacturers to understand their strengths and distribute work based on their competencies. We found that some manufacturers may be proficient in extrusion production but not in machined components. Traditionally, it was easier to aggregate production to reduce the number of suppliers and logistical overhead, but at this point, we’re at the scale where it makes more sense to have manufacturers focus on their core competencies to have the best quality possible.

Production space changes

Since moving into our new space in north Waterloo in November 2023, our space has adapted significantly. We’ve implemented new racking and equipment to increase the storage capacity of our production area. However, as we increase our batch sizes, our demand for space will increase as well. At this moment, our team is working on expanding the production area with potentially taking over more of our current building, as well as looking into a second space for warehousing.

Design changes and challenges

When working on the first batch of AltMills, we encountered a number of problems, some we were expecting and some we weren’t. Much of MK2 development is to address and improve the overall manufacturability and ease of customer assembly.

Extrusion

As we found when we first developed extrusions for the LongMill MK2, we knew that ensuring the flatness and straightness of the new extrusions were going to be critical in ensuring the precision of the machine. With the AltMill, with larger rails and the addition of linear guides, tolerancing was going to be an even more important part of the process.

Having material furthest from the center of the axis of rotation or flex offers the most rigidity in a structure. This is why in the initial design, the inside of the rail did not have any cross bracing. This might be counter intuitive, but actually is the most optimal way to design the rail. However, what we learned was that having some sort of cross-bracing would improve the straightness of the rail in production. While there is a small tradeoff in weight and potential performance, these differences are negligible for the added benefit of having higher production yield.

The original design and the current design both use machined surfaces to ensure that even with some deviation in the straightness and flatness of the rail, the linear motion would still mount without binding, but we found that in extreme circumstances, the rail would be so bent that the center of the rail wouldn’t get machined at all. These rails would need to either be re-machined or scrapped.

Another unexpected small benefit was the fact that the cross-brace increased the resonant frequency of the system itself so that the machine “rings” less.

Additionally, to aid with assembly, the Y-rails come with a small extruded “ledge” that helps keep the crossbeams supported and straight. This also improves the speed of assembly as the crossbeams can be held in place by the ledge while being bolted together, and the table does not need to be flipped twice during assembly to mount the table legs.

Crossbeams also now mount using a custom tall-head screw, making it impossible to drop into the rail, and improving accessibility of the screw head for easier assembly.

To add one more change to the Y-axis extrusion design is the integrated dust cover for the ball screw, instead of the stainless steel covers used on the MK1, which serve the same purpose, but reduce the assembly time and total part count. The addition of the ledge for the drag chain also helps keep it aligned during use. This recessed area also exists on the X-axis rail to help align the drag chain as well.

A last subtle difference in the MK2 extrusions is the consistent use of a more fine bead blasted and anodized finish on all extrusions including the crossbeams. This is more costly than the unanodized crossbeams used in the MK1 AltMill, but greatly enhances overall polish of the machine – even if these parts get hidden by the wasteboard.

Machining

One aspect of the manufacturing that proved to be a larger headache than expected was with the threading of the extrusion, notably, the M4s used with the linear guides and end tapping with the crossbeams. With the manufacturing of the LongMill MK2, we ended up developing a system to tap the extrusions in-house, especially since we had also started cutting rails for each of the various sizes for the LongMill as well. However, given the larger number of tapped holes, we had to bring the tapping out of house.

We found that some of the tapped holes had weak threads, causing them to strip during the assembly of the linear guides or when installing the crossbeams.

We’ve improved the quality control and documentation so that our manufacturers are able to catch poor threading, however, we recognize that ensuring proper threading would always be a part of the manufacturing process, so we are working towards bringing the machining and tapping in-house as well. As a redundancy, threaded sections of all rails have been strategically thickened for reducing the likelihood of strip-out when over-torqued.

Wire management

One of the common criticisms of the AltMill was its lack of well-thought-out wire management. This means that users would end up with a pile of wires at the SLB. Since all of the motor cables are the same length, depending on how far the motor is from the controller, the user would end up with varying amounts of excess cable. Additionally having bundles of long cables going to each corner of the machine can be unwieldy and prone to assembly error.

The MK2 implements new wiring that comes with pre-determined lengths and is pre-bundled for each axis. We’ve decided that although the packaging and supply chain may be a little more complicated on our end, ultimately, the improved tidiness and ease and speed of assembly would be worth it. This means that each cable is labelled and comes to an exact length to reach the controller. This also makes it easier to catch errors in assembly as wiring plugged into the wrong location would also be more apparent due to different wire lengths.

Additionally, each cable harness now includes an integrated limit switch cable, meaning less individual cables to route during assembly, as well as an easier time to identify where each limit switch plugs in.

Limit switches now connect to the integrated wire harness using a small locking connector. This makes installation of the switches and wiring a bit easier, as well as allows for easy replacement of limit switches if needed.

This work is also done in conjunction with adjustments to the front and back motor plates used on the Y-axis to utilize the inside of the extrusion to hide and protect the wiring. Additionally, we’ve made some changes to the SLB-EXT controller case to make wire management easier and cleaner.*

Please note that changes to the SLB-EXT are expected to come near the middle of the AltMill MK2 batch. Both controllers are the same and are cross-compatible with each other.

Motor covers

On the AltMill MK1, motor cables exit from the rear of the motor and curve backwards towards where the cables are routed from. In some instances, this could cause connectors to fall out, or individual cables to break in extreme cases. Early on, right after launching, the individual cable crimps were changed to prevent these individual cables from breaking or coming out, but it was still possible to have connectors become come loose from their socket.

On the AltMill MK2, molded plastic motor covers are used at all four motors to:
-Mechanically secure motor connectors from coming loose
-Provide strain relief for each cable harness and redirect this towards its cable routing path
-Provide protection of the motor and connectors without impeding any heat dissipation of the motor.

Backwards compatibility to AltMill MK1

It’s important to state here that the updates and changes made to the AltMill are primarily for ease of manufacturing and assembly. If you already have a AltMill MK1, it’s unlikely you’ll need or want to change or upgrade your machine to a MK2. Many if not most components are still cross compatible, which means that some replacement parts that will be available for the MK2 will also work with the MK1.

If I have an AltMill MK1, can I update it to the MK2?

If you already have an AltMill MK1, most of the parts are backwards compatible with the MK2. However, most of the updates made are to improve the assembly and manufacturability of the machine, so if your machine has already been assembled, there is little to no practical advantage to updating your machine from a AltMill MK1 to a MK2.

We will not have parts immediately available for purchase, but we are working stocking and uploading parts that can be used between the two machines.

Additionally, if you already have a MK1 on order and would like to change your order to a MK2, please contact us. Please note that changing your order from a MK1 to a MK2 may delay the shipping of your order, plus have a price difference, as we will complete shipping of AltMill MK1 before AltMill MK2.

Electronics and software remain the same and will continue to be updated in line with the MK2. Resources and instructions, and tutorials will still continue to be relevant to both versions of the machine.

If I have an AltMill 2×4, can I update it to a 4×4?

Theoretically yes. To update it to a 4×4 size, you’ll need to replace the Y-axis rails, ball screws, motor harnesses and add an additional 2 crossbeams. It is our plan to have, as we currently do for the LongMill, parts available for purchase in our store for modifications and changes. However, the cost of the conversion on an individual basis may be high, and we don’t have a specific timeline or roadmap for a dedicated kit or instructions, so we strongly recommend ordering and committing to the size that you plan to use for the long term.

Pricing

Base price for AltMill 4×4 goes from $3990CAD to $4290CAD or $2950USD to $3160USD, ($300CAD difference or $210USD difference).

Base price for AltMill 2×4 to be $3890CAD or $2790USD.

Pricing for spindles and other accessories remains the same.

We are adjusting pricing for the AltMill to reflect some of the changes and improvements we’re making to the MK2 and better reflect our current costs for production.

The AltMill 4×4 MK2 and AltMill 2×4 will be available to order with updated pricing on Jan 29th, 2025 11AM EST. On Jan 29th, only the AltMill MK2 versions will be available for order.

Please note that this is expected pricing but pricing may change.

Hey everyone. I’m excited to share more details about the AltMill 2×4 (the AltMill with a 4×2 ft working area) and other sizes coming soon. We are expecting the launch of the AltMill 2×4 A few months ago, Ben took some time to put together a version of the AltMill with a 2×4 foot (approximate) working area using spare and scrap parts left over from production and posted a video about it. Since then we had a lot of interest in smaller versions of the AltMill.

Availability to order the AltMill 2×4 is tentatively scheduled for Jan 29, 2025 and expect to ship at the end of March. The AltMill MK2 2×4 will be available for order on Jan 29, 2025 at 11AM EST.

AltMill MK2 2×4 (machine only) to be $3890CAD or $2790USD. Spindle and Dust Shoe Kit pricing at $690CAD/$515USD

Since showing off this version of the AltMill, the response from the community has been overwhelming, encouraging us to develop and work on exploring different sizes of the AltMill.

Why different sizes?

After building and testing the AltMill, it became clear to us that the design and platform had a lot of potential to be used in a lot of different applications. The main innovations of the AltMill come from optimizing the design for rigidity while making it as easy and efficient to assemble at scale, which translates to different sizes as well.

As it stands, we believe we haven’t fully unlocked the power of the AltMill. We still have a lot of development and progress to make with:

• Higher power spindle options
• Automatic tool changers
• Coolant options
• Advanced clamping, vices, and other hold-down methods

The main goal for building all the different sizes, ultimately, is to serve a larger audience who want to use their machines for different applications beyond just the typical woodworking projects that our machines and industry have been focusing on such as:

• Aluminum milling
• Steel milling
• Plasma cutting
• Fiber laser cutting
• Automating tasks such as drilling and tapping

Fundamentally, the AltMill serves as a platform for CNCs designed for many different uses and leverages development across all of the different platforms to trickle through the whole ecosystem.

Who is it for (AltMill 2×4 and smaller)?

We’re not a 100% sure yet but here’s some of our thoughts.

People who want to do small-scale production for a specific part:

Although a larger machine is more versatile, for users who want to have a machine suitable for machining specific products and parts, a machine just large enough for that specific part may be the best option, especially in space-constrained locations. For example, the AltMill could be jigged up to make guitars in a production setting, as the workspace is large enough for a full neck and body.

Another advantage of the AltMill is that businesses that need to do production can in theory order and have a machine shipped to them directly on short notice (or at least once we finish optimizing our production), allowing them to scale production quickly when they need additional machines.

Education or use in an institution:

We’ve also gotten interest from people who want to use CNC for teaching or institutional use, where the focus is less on producing parts and more on learning and testing. This could be in CNC software companies testing their CAM software or colleges that need lower-cost CNC machines that are robust enough for students to use while fitting in smaller classrooms.

The AltMill works on the same core technology as any industrial CNC machine, which means that it can provide an entry into CNCing without the risks and costs which come with industrial machines. The open-source nature of our designs and company also allows for institutions to adapt their machines to their needs as well.

For fun:

While AltMills are not cheap, they do come in at a price point that makes it accessible to most dedicated hobbyists. We expect pricing for all versions of AltMills to be around the current price of our 4×4, with variations based on size and configuration. This means that users may choose to buy a CNC machine just for the heck of it.

Sm-AltMill (Small AltMill)

Concepts of a smaller, metal milling-focused CNC internally called the “YesHappy” or “Sm-AltMill” have been tossed around in the shop for some time. From our perspective, we feel there’s a gap in the industry for a small, benchtop-sized CNC machine for milling aluminum and steel. While there are some options in the $2000-5000 range, we feel they are either underpowered and only good for small parts, and consumers need to spend around $10,000-$30,000 to purchase a smaller milling CNC or VMC.

Here’s a list of machines that we found that are sort of in this space.

Machine	Price (CAD)	Cutting Area(in)	Spindle Power(kW)	Motion System	4 Axis Compatible From Factory
Makera Carvera	7800		0.2	Slide Bearing	Yes
Shariff DMC	4550		2.2		No
Sainsmart Gemnmtsu	1945		0.4	Delrin Wheels	No
Yorahome Crossriver 6060	4107	24x24x5.8	0.5	Linear Guide	No
Carbide 3D Nomad	3640	8x8x3	0.12	Slide Bearing	No
Source Rabbit Quantum	12800	13x13x4	1.4	Linear Guide	Yes
Langmuir MR-1	6500	23x22x6	2.5	Linear Guide	No
Kitmill AST	11000	8x5x4	0.1	Linear Guide	No
Stepcraft-3 D420	3000	12x16x5	1		No
Coast Runner					No
Onefinity Machinist	2400	16x16x5	Makita	35mm Rail	Yes
Bantam Tools	11000	7x9x3		Linear Guide	Yes

So where do we land for this? Here are some considerations:

• With our software and hardware stack, we can support advanced functionality such as 4th axis support, coolant control, closed-loop steppers, and more without additional development, since functionality has already been worked on and developed for AltMill and LongMill already.
• Since we are already assembling and building AltMill at volume, we can take advantage of economies of scale for many of the parts used in the other-size machines.
• The rigidity and accuracy of the AltMill generally exceed the majority of the machines on this list and can be optimized further. Based on our testing, we’re able to reach material removal rates on the regular AltMill 48×48 compared to the highest-powered machines in this list, and we expect that a smaller version of the machine would increase the overall rigidity to continue to meet or exceed performance across the board.

There are a couple of things that we’re working on now including:

• Reaching out to people in the machining community to get their thoughts on this sort of product
• Figuring out the balance between cost, features, and performance
• Playing around with different add-ons such as ATC and coolant
• Building a small batch of beta units
• Testing metal-specific tooling

Larger machines (AltMill 4×8)

On the other hand, we’ve also been getting a ton of interest in a 4x8ft version of the AltMill. Our team has been considering this as well, and identified two main short-term challenges and one main long-term challenge in bringing this to market.

First is the packaging. One of the main advantages we have is being able to pack and ship everything through a courier like UPS. This avoids the need to deal with complicated freighting and equipment needed to load and move large CNC machines. However, using a courier for very large shipments can be expensive and sometimes not possible depending on the size and weight of the order. Additionally, shipping items through couriers run a higher risk for damage, as shipments go through many hands and get stacked and piled on top of other shipments.

We believe that using the courier method does make things more accessible since we can deliver CNC machines to residential locations. However, the larger and heavier the machines become, the more difficult it is to work around the limitations. That being said, we’ve seen lots of examples of this, and we believe, we can sort out something that works.

The second challenge is with power transmission. Since the Y-axis needs to get longer, it also means that the Y-axis ball screws will become more prone to whip if we keep the same design. This can be mitigated with a number of options, such as using rack and pinion, larger ball screws, or something else, but this means that we’ll have to engineer another way to move compared to the existing solution. Of course, designs and solutions already exist, and we believe that we’ll be able to figure something out in this area too.

Lastly, the other, perhaps long-term challenge comes down to our company scale. Larger machines take up more space, and although we just moved into a larger office about a year ago, we’d be looking at moving into an even larger space as soon as we start production for 4×8 ft CNCs. Additionally, and perhaps the even bigger challenge, is hiring and onboarding more team members to support the new product.

With that in mind, we do believe that there is a space in the market for an AltMill 4×8, and we have been chipping away at the design and logistics to eventually bring it to market. Make sure to stay tuned for new updates.

Pricing

There are some fixed costs associated with all versions of the AltMill, such as:

• SLB-EXT controller
• Spindle (although the specific version may vary depending on the use of the machine)
• Closed-loop stepper motors
• Gantries (although there may be variations for machines designed for milling metals to accommodate vices and additional workholding)
• Couplers, bearing blocks, and other assorted hardware

On the other hand, costs for items that are size-dependent include:

• Linear guides
• Rails
• Packaging and shipping

We predict that material costs for smaller machines will be relatively close to the 48×48 AltMill. Some additional costs include:

• Resource and support costs for each variation of the machine
• Unique packaging and assembly costs
• Development costs
• Additional machine-specific accessories such as coolant support and vices

All in all, we don’t expect pricing to be dramatically different compared to the current AltMill, which we believe is well-priced on its own. Customers should expect pricing for the AltMill 2×4 to be similar to the current price for an AltMill 4×4. Finalized pricing will be available near or at launch.

Next steps

Production for more AltMill rails is now in production, which includes approximately additional rails needed to build around 100 AltMill 2×4 We’re expecting them to arrive around the end of February, which means we’ll have the first parts needed to start building around 100 units.

Our team is currently working on media and marketing materials to prepare for the launch of AltMill 2×4 on the store, which is tentatively scheduled for Jan 29th.

We expect AltMill 2×4 to start shipping in March.

Additionally, we are in production for an additional 25 sets of rails and parts for a 16×16 inch working area machine (Sm-AltMill), which will be focused on metal milling. We do not have a specific launch plan for this yet, but we are collecting feedback and doing market research to understand how we want to configure the design for this. We will be reaching out directly to potential users for sales of the first batch, so if you’re interested, make sure to fill out the survey.

We are expecting the Sm-AltMill to be sold and built on an individual basis and customized and tested for different uses, which means that they will not be publicly available for sale at this time.

FAQ

Is there going to be a way to upgrade from a 2×4 to a 4×4?

It is likely we will have a kit available, but we likely will need a few months after the launch to sort out the product and resources for size changes, so we recommend picking the size you’ll be committing to up front for now.

What is the footprint of the AltMill 2×4?

The footprint is approximately 52in wide and 39in deep. From the bottom of the foot to the top of the motor, the height is approximately 56in.

Do the legs come with the AltMill 2×4?

Just like the AltMill 4×4, the AltMill 2×4 comes with steel legs.

What accessories work with the AltMill 2×4?

Any accessory that works with the 4×4 will work on the 2×4. This includes any spindles, gControl panel computer, Vortex Rotary axis, and more. We expect that future add-ons and features designed and developed for 4×4 will work on 2×4 as well.

What is the price for an AltMill 2×4?

Official pricing has not been established, but users should expect pricing to be similar but slightly less than a 4×4.

When are AltMill 2×4 expected to ship?

2×4 machines are expected to start shipping in March 2025.

Where can I buy an AltMill 2×4?

Pre-orders will be available on our website at the end of January.

Will there be any other sizes of the AltMill?

Besides the Sm-AltMill with a working area of approximately 16×16 inches, we don’t have any immediate plans for other sizes at the moment.