The Saga of the Spring Loaded Anti-Backlash Nuts

IMPORTANT: This blog post will be updated with more details once we receive the first batch of prototype nuts. They are expected to arrive in the first week of February.

UPDATE TO IMPORTANT: We received the nuts for testing. Good news is that the T8 nuts are pretty good, but the T12 nuts have threading issues. We should be able to fix some of them and have them available for sale pretty soon, and we are working on making sure for full scale production they will have this ironed out.

Back in August 2023, we shared with the world a new “spring-loaded anti-backlash nut”. The basic idea was to address some of the pain points of the original Delrin Anti-Backlash nut which we’ve been using on LongMills since the first machine was released.

Early prototypes showed a lot of promise, so we decided to move forward on iterating on the design and moving it forward. However, throughout the project, we ran into different issues and roadblocks like all development projects.

We now are in the process of producing the first batch of nuts, and we plan to eventually phase in this new design for new machines. Additionally, customers can purchase ones to replace the nuts they already have in their machine. In a way, I hope that this can be sort of a “best-of-all-worlds” solution, over belts and ball screws because:

  1. Unlike belts, lead screws don’t stretch over time
  2. Unlike ball screws, they don’t need lubrication and are dust resistant.
  3. A lead screw plus spring-loaded anti-backlash nut is cheaper than a ball screw and easier to assemble, and also pretty comparable in cost with less complexity compared to a belt drive system (personal opinion kind of)

The only downside of this system is that technically this system is less precise than a ball screw, but in the context of hobby CNCing, totally acceptable and in practice, indistinguishable in this type of woodworking.

My hope with this new design is to primarily address two main issues with the old version of the Delrin anti-backlash nut. The first is the need to adjust the nut. Because the old version uses a screw to push apart the threads and is fixed in place, the user must adjust the screw as it wears down. In practice, this isn’t a big deal since the nut wears down slowly and the difference is minimal, but the issues arise when they are adjusted too tightly, causing premature wear, or not tight enough, introducing more backlash and thus sloppier machining.

The “original” T8 Delrin Anti Backlash Nut and the history behind T8 lead screws

So this is my sort of knowledge behind the history of this lead screw design and how it came to be, at least in our context. Back when we first started the company in 2016, home consumer 3D printing was still a pretty new concept but had established itself in the market enough to have some standardized components used between most 3D printers. One of these standard components was the T8 lead screw.

At the early days of building CNC machines, notably the Mill One, we used standard 3D printer components, namely the T8 lead screws as power transmission for the gantries. We also used these brass nuts that were also standard between 3D printers like the one below:

One of the main issues with these nuts was that since they had no backlash compensation, they would lack some accuracy, especially if it wore out.

We also used some spring-loaded versions of these as well, but they also sort of sucked, mainly because the springs were not strong enough to resist backlash at higher loads.

Spring loaded brass anti-backlash nuts

Going into designing the LongMill, we recognized that using the brass nuts wouldn’t cut it for a larger more powerful machine, so we found another nut design created by OpenBuilds that addressed the backlash issues. And they did work pretty well without many issues. Additionally, there were a lot of manufacturers that were making these for cheap so it was a pretty affordable option in the application, although, over time, we ended up manufacturing them custom to improve the quality of the nuts.

The idea behind the spring-loaded nut

One of the main weaknesses of the original Openbuilds nut is that you need to adjust it over time using only a single screw that is easy to under-tighten or over-tighten, causing issues due to being adjusted incorrectly. We see the issue of motors stalling because of this, especially for first-time users. If we could design a long-lasting nut that didn’t need any adjustment, then we could eliminate this main pain point.

We found some interesting designs in the market that use a “radially” loaded design, which basically pushes the threads into the root of the lead screw. Some of the main benefits of doing so is more even wear in the nut, leading to a longer life and higher precision. Here’s a good example of another radially loaded anti-backlash nut.

The initial designs that we came up with uses two split-threaded “arms” to pre-load the nut. We chose this because it allows us to keep the profile that we need to drop into where the old nuts were.

Prototype 1

In August 2023, we launched the first version of the new, spring-loaded anti-backlash nut. This was a limited batch of 100 sets, which were sold as working beta version of the product so that we could get real-life testing and feedback. Out of the 94 orders shipped to customers, we had fairly promising results.

Forms response chart. Question title: What are some improvements you've noticed with the new Spring Loaded Anti Backlash Nut (select all that apply)?. Number of responses: 21 responses.

The main feedback that we got was that the nuts feel a bit “loose”, and the main suggestion was to use stiffer springs, as well as a lot of people wanting a T12 version to come out as soon as possible.

Here’s some thoughts and notes on the responses and results from our own internal testing:

From our testing wearing down the nuts, the springs were able to account for backlash, but because of the angle at which the forces were being applied and the stiffness of the springs, there was a concentrated area of wear that would affect the performance of the nut.

Concentrated wear on the top edge of the nut

Overall, they did work, and pretty well for the most part. However we felt that if we were going to invest in this system in the longer term, that improvements to the design should be made before full scale production.

Prototype 2

To address the issues from the first prototype, we tried a whole bunch of different ideas to find ways to improve the nut. Some of these include:

  • Using a flexure, but due to the limitations of injection molding and machining, was scrapped
  • Using a circlip as a spring, which worked well but was not easy to determine and adjust the spring force.

We did however try making changes to the bending areas of the arm by tapering them down and having the spring push horizontally rather than vertically.

Additionally, it’s worth noting that one of the other main differences between this nut and the old version is the manufacturing complexity. We have several slots and features that make it a bit more complicated and expensive to make, so we started exploring making injection molding a blank for the nut itself and machining in the critical features.

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This allows us to reduce the bulk of the machining, which is a significant part of the part cost, enough so that we can keep the same cost for the new nuts as we old ones.

The main issue with the first batch was that there was deformation in the nut itself causing the dimensions to be warped. This meant that the threads were ok on some nuts and way too tight on others. Secondarily the threaded hole did not center properly causing the lead screw to be off-center as well. Thus through testing, we found that this would cause issues with binding.

After discovering this, we went back to the manufacturer, who made changes to the mold, machining, and clamping processes. We also sent them additional documentation for proper mounting to share the context of where the critical tolerances were. After a week of tweaking, you can see in the new video from the manufacturer that the nuts thread on much more smoothly.

Conclusion

At the time of writing, the first batch of final production nuts is on the way, and we will test, assemble, and post them available for sale when they arrive.

We plan to sell this first batch to current users, and if the nuts work well and people are happy with them, we can transition to having them available for kits as well. However, we don’t expect this to be the case for another 6 weeks since we are in production for the complete batch.

February 2024 Production Updates

Hey everyone, welcome to our February 2024 Production Updates.

Media Room and Workshops

Since we’ve moved into our new space, we’ve dedicated an area as a “media room”. The idea is to build a space that allows us to make content more quickly with dedicated space, lights, and machines for filming and education. Additionally, we’ve gotten a lot of interest in doing workshops, and so we’re now looking into planning workshops in the space as well.

If you’d like to provide some feedback and let us know what sort of workshops and content you’d like to see, please check out https://sienci.com/2024/01/10/fill-out-our-cnc-workshop-survey/

LongMill MK2s

Production for the LongMill continues to move smoothly. Orders are shipping out within one week, however we are running low on controller boards. Lead times may get longer this month.

Check out this new racking we got for all of the rails! It looks very visually satisfying.

Injection-molded middle feet that are used for supporting the rails have finally completed production and are on the way to us. We expect these feet to arrive in early Feburary. For those who haven’t been following along on this change, we decided to start injection molding these parts since we make a lot of them using the print farm and we crossed the point where it would be faster and more economical to injection mold them. It should be noted that this change is to improve production efficiency and reduce costs, but won’t make a difference to the LongMill’s performance.

Injection molded feet

The bristles that we use for the LongMill dust shoes have come in earlier this year but we have been dealing with quality issues. We have been able to use some of the good bristles, but we’re also working on sourcing a new manufacturer to improve the quality.

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We are now starting production on Batch 9 LongMill MK2s. We currently have around around 750 LongMills in stock, and expect to start shipping Batch 9 machines in the spring of 2024.

Spring Loaded Anti-Backlash Nut

Second batch of prototypes

I know a lot of people have been anxiously waiting for the spring-loaded anti-backlash nuts. While they seem simple, these have been a really fascinating but challenging project as we needed to make changes and considerations to the design and manufacturing process of the nut.

For more details about the process of design and making the nuts, I wrote another blog article. The first 200 sets of T12 and T8 nuts are expected to arrive in the first week of February. Please note that the blog article will include more updates once the first batch of prototype nuts arrives.

Vortex Rotary Axis and LaserBeam

Parts for the Rotary Axis have arrived and are being packed and assembled. We have another 300 units in stock now.

Ikenna and Abeiku are also working on a new magnetic mount design and also a riser mount to be used with the Vortex to allow for easier laser engraving on round objects soon, so make sure to keep an eye peeled for that.

AltMill

We have our major components arrived here and are working on putting together and testing the first prototype. Based on looking at the linear motion and extrusions, everything looks great and we’re excited to get everything in to start building the first batch.

AltMill table, Daniel for scale

If you’re interested in ordering an AltMill, make sure to fill out our form.

Here are some other updates:

  • While we have received one set of extrusions, the full batch of 50 sets have had some QC issues and are being worked on now. We expect them to be finished in the next 2 weeks and get prepped for shipping
  • We have received a few additional closed-loop stepper motors for testing and will be working on having them set up for testing
  • We are working with Andrew at Expatria to figure out what modifications we need to make for the SLB to allow for use with AltMill.

Also, check out this new logo that Leandro made for the AltMill.

We are tentatively looking at a launch date for the end of March. We’ll keep people updates so make sure to follow along on the development through the blog and such.

CO2 Laser

Ikenna and his team have been continuing to work on the CO2 Laser. Here’s a photo of the mockup in progress.

I probably won’t be continuing to put updates for this project on the production updates here because Ikenna will make a separate post as updates come. Make sure to sign up for the CO2 mailing list for all updates as they come.

Sienci Router

Testing with the 400 watt motor looks to show that using BLDC is a promising technology and shows that power output even at 400 watts is comparible to the Makita router. However, we feel that to bring the most value to users, having a bit more power will be beneficial since:

  • Cutting using larger bits, such as the surfacing bit causes the Makita router to bog down
  • Additional headroom allows us to run the LongMill faster alongside other future improvements to speed and rigidity
  • Potential to be a viable option for higher-end machines and the AltMill.
  • Creates a differentiation between our router and the Makita router

Having a larger motor is more expensive, but still within our budget. Pricing is still yet to be determined, but we believe that if we have an option around the $250 mark will allow us to provide a tool that sits somewhere between a traditional router like the Makita RT0701 and a 3 phase spindle.

A second batch of motor samples are expected to ship in the first week of Feburary. We are also in the design and sourcing stage for the motor body and bearings.

A section view of one of the router designs

SuperLongBoard

Development continues for the SLB and third version prototype is currently in testing. Here’s some news:

  • SLB resources continue to be developed ahead of shipping
  • E-stop injection molded case, buttons, and circuitry have arrived for testing, and have started on full scale production
  • Enclosure parts are getting prepared for shipping

Otherwise we are just working through general bug fixes and testing as usual.

Demand for the SLB has been strong, and we are expecting to sell out of the first batch before we start shipping, so we are working on

If you haven’t checked out Chris’ last update, make sure to read it here.

January 2024 Production Updates

Hey there, thanks for checking in on our January 2024 production updates!

A lot of info to share here, some of which are updates we talked about in the December 2023 update here, so if you haven’t read it yet, then make sure to check it out.

Holiday Break

Please note that our offices will be closed from Dec 23 to Jan 1st. We will reopen on Jan 2, 2024.

During this time:

  • Shipping of items may be paused until we return.
  • We may not have someone answering phones at this time.
  • Responses to emails may be slower than normal.

NEXUS taxes for USA

Due to the scale of the company and sales in the US, we may have to start remitting sales tax to some US States once we reach certain thresholds. Starting Dec 18, 2023 and going forward, we will be collecting and remitting sales tax for Florida.

We are continuing to work with our accounting and finance people to slowly figure out how all this tax stuff works, so keep tuned as things may change over the coming year.

Move complete

Our move is done! We are now completely cleared out of our 372 King St N, Waterloo location. For any appointments, mail, and packages, make sure to send things to our new address Unit 1B/1D – 120 Randall Drive, Waterloo ON.

LongMill Production

Production for LongMills continues to go smoothly, with most machines shipping out within a few days. With some people taking vacation at this time, it may be a little bit slower than usual, but we are also expecting to have a few new hands starting for packing and operations starting in the new year.

Vortex Rotary Axis and LaserBeam

Vortex parts are on the way and are expected to arrive around mid to end of January, at which point we will continue to ship Vortex. Orders are expected to take a few weeks to ship.

LaserBeam orders are shipping within a few days.

CO2 Laser

CO2 Laser development is now officially in progress! Check out the amazing video here:

Interested in following along development? Sign up for the mailing list here.

Want to help us understand what you’re looking for in a CO2 laser? Fill out the survey here:

https://docs.google.com/forms/d/e/1FAIpQLSffBHaWX0N8alf597e_5kbCjd_bsgglIzursC7rfZL8Pby68A/viewform

AltMill development

AltMill development continues to move along. We are now waiting for new parts to arrive for the AltMill. We were expecting parts to arrive by the end of December, but due to some initial shipping issues, we expect that it will be more likely to arrive by mid-January.

We’ve also started testing close-loop steppers with the AltMill prototype. With Daniel’s setup, we were able to achieve up to 17,000mm/min (around 670in/min) rapids on the X. We are waiting on a few more motors to come in to set up all of the axis, so that we can test them all simultaneously. For context, the max rapid speed set for the LongMill is 4000mm/min.

This is where things get a little dicey since the mass and inertia of the machine running that fast can definitely do some damage to a person. In practice though, having speeds that fast probably won’t matter that much without a spindle and bits that can handle it.

I have spent a few days in December working on a couple of personal projects with the AltMill prototype. Although this isn’t going to be the final version of the machine, I figured it would be a good way to start to understand the workflow of using a 4ft x 4ft machine. I also set up a Beelink computer and a touch screen for some testing of potential future interface for gSender.

Here are my notes:

  • I haven’t made anything that needs the full bed, but what I noticed was it is a lot more convenient to work with larger sheets because they need less processing
    • I can see myself wanting a 4×8 sometime down the line because you basically can buy one sheet and just keep cutting with it. I have been getting full 4×8 sheets and passing them through the back without cutting them down so far.
  • The machine is more solid and I have more confidence in pushing it harder. Because all of the defaults are set to the same/similar to the LongMill, everything seems slooooow.
    • Given this, I feel like going in the direction of close-loop zoomy steppers is going to make a big difference in the user experience
    • Having a chunkier machine does give a lot more confidence, especially not having to worry about stuff being adjusted correctly
  • Having the touch screen is actually mint
    • Controlling the machine is super easy, the keyboard and things pop up and disappear perfectly
    • The zooming sort of doesn’t work but you sort of dont really need it much
    • The networking to share files is basically seamless

We were expecting to receive the first set of parts at the end of December. However, due to some delays and issues with the shipping, we are now expecting them to arrive in mid-January. Once these parts arrive, we will be putting together the first prototype of the new design. It looks like the rails have actually come in but I haven’t gotten a chance to look at them yet.

If you are interested in getting on the list to order an AltMill sometime this year, make sure to fill out the survey and read the blog post here: https://sienci.com/2023/11/22/putting-the-altmill-project-back-on-the-burner/

A couple of people have asked us about the QA process. Here is my answer from the forum.

https://forum.sienci.com/t/altmill-cnc-update-whats-new/10369/9

I think that it’s hard to have a specific QA plan or process in place until we go into production. The fact of the matter is that the process depends largely on the actual scale of the production.

There are a few things that we learned from QA for the LongMill that carries over to the AltMill including:

  • Isolating parts and making them perfect, so that they can be eliminated as a source of error. For example. When we first started producing the LongMill, a lot of the parts were off the shelf, such as the coupler. What we found was that because the couplers from different manufacturers could be inconsistent at scale, we basically just designed and manufactured our own version at a higher level of specified tolerance. At this stage, nearly all of the parts that go into the LongMill are custom-made and redesigned internally, which has greatly improved the fit and finish as well as lowering issues that customers get with quality. The AltMill will almost certainly follow the same path, but likely even sooner because we have processes and manufacturer contacts that can make many of our parts.
  • Focusing on good design and ease of assembly will pay large dividends in production. There are many aspects of the AltMill that take the strengths and weaknesses in the accuracy of the manufacturing processes to ensure that the machines assemble easily and are to spec. For example, and something we mentioned in the AltMill update video, is that because while aluminum extrusion is generally considered a process that produces very high-accuracy parts, it also has a tendency to twist and warp during manufacturing, having machined faces and using a frame that self-aligns itself allows us to compensate for minor deviations to our specs.
  • The cost-benefit analysis of good quality always outweighs the cost of customer service. The result of having bad-quality parts and products is that we need to do customer service to fix the issues, which costs the company time and money. Some of these costs could be the part itself, shipping, the time from our technical support team, lower customer satisfaction, and lost time for the customer in using their machine. While the cost of the part might be a few dollars, after the time, troubleshooting, and shipping, the issue might cost us a hundred dollars or more. So basically in almost all cases, it’s a better cost-benefit to check our parts better and produce higher quality items.
QA report of the rails from the factory
Sample photos of the rail

I think generally speaking the AltMill will actually be easier to QA for, because we’re bringing more the assembly in house, which will allow us to make sure the machine works before we get it to the customer, and second, we are using more higher precision components around the AltMill so that there should be less issues that come from mismanufactured parts.

There are a few concerns we still need to test and address including:

  • Because the machine is running faster and experiences more forces, making sure that bolts don’t come loose over time
  • Tolerance for lack of maintenance, since components like the ball screw and linear guides need proper lubrication otherwise can fail prematurely

To answer some of the general questions we got in the survey…

Q: Any option to cut vertically?

A: I don’t think we are planning to build anything that would facilitate this, and the weight of it would make it much more difficult. It seems a bit impractical at this size, even though I feel pretty confident that the hardware could handle it.

Q: Will the AltMill use the SuperLongBoard?

A: Not exactly. The SLB doesn’t offer any outputs for controlling external drivers except the A-axis/4th axis. However, we are most likely going to make a new version of the SLB that has outputs for the drivers and no integrated drivers, so that we can offer the same functionality of the SLB and use external drivers.

Q: Will this support an automatic tool changer?

We don’t have specific plans to make a ATC right now, but with the IO on the modified SLB, you should be able to integrate your own.

Q: What is the overall footprint?

The AltMill will have a minimum cutting area of 4ft by 4ft (with some extra travel room to spare), with the ability to pass through the back of the machine. The footprint is approximately 59 inches by 59 inches square. Size might change slightly at production.

If you want to learn more about the AltMill project, expected pricing, and more, please check out the video and the blog here:

Sienci Router

After a bit of a mixup where we had the motor sent to the wrong address, we were able to get a new one and start testing. As we were discussing in the last update, we decided to dive into using BLDC motors because of the benefits we feel like worth getting over the universal motors we initially were exploring.

We found that for BLDC motors running at this higher voltage, there weren’t a lot of options we could find. We did find an off-the-shelf motor that are used in commercial grade blenders we got a sample from the manufacturer, and hacked together an old Makita router to build a sort of BLDC router frankenstein.

The motor that we got maxes out at 8100RPM, which isn’t the optimal speed for the type of cutting we want to do, but for the sake of testing, we tried to do some comparisons between the different routers we have here. We also have a power output limit of 400 watts.

Some notes and results from testing

Basically what is important is the torque of the motor at the given speed, since the motor can overcome the cutting forces on the bit. From Johann’s observations, at the lowest RPM setting on the Makita, the router stalls out at a torque of 0.47N.m, pulling 12.69A or around 1500 watts from the wall. The BLDC motor stalls at 0.45NM but only draws around 400 watts from the wall.

Additionally, the motor behaves the way we wanted it to, which is to run at the same RPM until it stalls. This is important because when a CNC machine starts cutting, there is a situation where if your RPM drops and your chipload and forces increases, it bogs the spindle or router down even more, eventually causing more issues.

It should be noted that based on our understanding of universal motors used in the Makita, the torque of the motor drops proportionally to it’s RPM, which makes sense because it is also partially limited by the amount of power it can draw from the wall.

The BLDC however is designed to keep the same level of torque through the whole speed range. We are specifying our second prototype to have a torque of 0.55N.m, which means that at 30,000RPM, it will draw a full 1500 watts, which in theory would match 1.5KW spindles. I think that in practice however, there aren’t much or any scenarios users would need to run their routers so fast, and we are focusing on having a max RPM of 24,000 instead.

We believe that if we modify the motor to run at the higher RPMs, the BLDC limited to 400 watts will run close to identical to the Makita router. However, considering that there are still situations where the Makita bogs down on the LongMill, if we can get a bit more headroom, that would be ideal.

Based on some general calculations, if we target a 0.55N.m spec on the BLDC, we can get about 1.3-1.5Kw of power, which may be close to on par of a spindle.

There is still a lot of testing and benchmarking to do, but we are continuing to make progress. The next sample will probably take 2-3 weeks to be made, so I would guess we’ll have them at the start of next year. In the meantime, Johann has been working on the mechanical design and housing for the motor.

gSender

Meeting to talk about the new features in gSender

The gSender team have been continuing to work hard to put together a new version of gSender which will merge features and functionality from gSender Edge to the main version of gSender. For complete list of features in gSender Edge, please check out the resources here.

  • Improvements and bug fixes for running the Vortex
  • Probing with touchplate on all corners
  • Communication, flashing, and additional features for the SuperLongBoard
  • Faster and smoother gcode visualization screen
  • Warning for zeroing
  • Improvements to the gamepad/controller functionality
  • Improvements to remote mode/pendant functionality
  • Maintenance warnings and tracking

All of our beta testers and myself have been using the latest version of gSender Edge to test the SLB and our machines and help with the bug fixes. So far the extra features have been amazing. You can also check out the latest version, V1.3.10, here.

We expect to have more updates and information come out around the middle to end of the month when the new version of gSender is ready.

1/4″ Precision Collet for Makita RT0701

Some people have been asking us about replacement 1/4″ Makita RT0701 collets, and Garrett wanted some for his store so we made a batch of them together.

These collets work with any Makita RT0701 router. If you ever lose yours, you can now get them from us!

You can now find them in our store here: https://sienci.com/product/1-4-precision-collet-for-makita-rt0701/

December 2023 Production Update

Hey everyone, here’s our December production update! Many things happened in November.

On a side note, I just turned 27. I think it’s sort of crazy I’m in my “late-20s” now?

Holiday Break

Please note that our offices will be closed from Dec 23 to Jan 1st. We will reopen on Jan 2, 2024.

During this time:

  • Shipping of items may be paused until we return.
  • We may not have someone answering phones at this time.
  • Responses to emails may be slower than normal.

We will have a shipping cut off of noon on Dec 22. Please place your orders if you’d like to have it shipped before the end of the year.

Moving

Moving continues to chug along, with the final moving to be done before the end of the month. Please note that response times and shipping may be a little slower than usual.

Our new address will be Unit D, 120 Randall Drive Waterloo.

LongMill MK2 Orders

LongMill orders continue to ship as usual. We were a bit low on bristles for the dust shoe, which meant that some orders took a few days extra to ship.

Thanks to a grant from the government, we are getting a new CO2 laser cutter and CNC mill partially subsidized for prototyping and production use. We’re planning on taking the old CO2 laser which we’ve been using for the last 3-4 years and taking it apart for R&D use for our CO2 laser project.

We are now waiting on injection molded feet for the LongMill, which we expect will help reduce our reliance on the 3D printing farm by about 25-30%. This should help us free up more capacity for printing other parts, such as dust shoes and LaserBeam parts so that it will be less of a bottleneck for production in the future. Ron, our print farm manager, also started working with input shaping, which is a feature that allows for faster movements with less resonance by analysing the printer’s movements and adjusting its movements to cancel vibrations. This also is helping to improve print quality and increase print speed by 15-25%.

LaserBeam and Vortex

LaserBeam continues to ship as usual. We are currently waiting on a new batch of heatsinks, drivers, and cables to arrive in the next few weeks so that we can stockpile more units.

Vortex also continues to ship but we now have around 17 (at the time of writing) left. Probably by the time this post goes out, we probably will have a few less. There is another batch in production now for 300 units, which should be ready to ship early January.

SuperLongBoard

Chris just put out a update video about the SLB which can be found here:

I’ve taken a step back from helping Chris with the testing side of the board currently and working on some of the manufacturing along with Daniel, but it appears that the testing in the back room continues to happen at a blazing pace. I just placed an order for another 40 controllers to ship in the next few weeks for final testing.

The designs for the SLB controller case have now been finalized and in production. We expect samples from production to be ready in the next 3 weeks, and parts to arrive in the new year. One of the main differences for the new controller is that it is designed to mount directly to the Y rail on the LongMill, which allows it to take a bit less space on the workbench. However, users will still be able to mount their controller using the screw holes as well.

Design for SLB case

We are also wrapping up the design for the new E-stop buttons and macro buttons as well now and starting production for it this week.

Pre-orders are slated to come in December 4, so make sure to keep your eyes peeled for that! For more info about the pre-order, please check the Blog post here.

AltMill

As we were alluding to in the previous updates, we’ve started working on the AltMill. Kelsey and I are currently working on the shipping of the first batch of parts for the AltMill.

For the latest update, please see our blog article.

Thank you to everyone who filled out the survey. It looks like we have quite a bit of interest in the AltMill. We’ll continue to post updates here and prepare for pre-order availability as we move forward with production on the first batch. At the time of writing about 5 days after the survey went out, we have over 50 respondants, half of which are ready to put down money to get the new AltMill.

Initially I was expecting sales for the AltMill to start out pretty slowly, maybe 15 machines per month, however I feel pretty confident that sales will be much stronger especially given the lack of information we have out for the AltMill at the current time.

Sienci Router

Continued development on the Sienci Router has been fascinating, especially as Johann and I have been looking beyond AC universal motors found in most power tools like the Makita RT0701.

One of the main important things we’ve been looking at has been the efficiency and actual power output of the Makita router. Based on loading and testing the router, we see that the true power output of the router is much lower than the 1.25HP rating in some scenarios.

In theory, this means that a more efficient motor could use less power, but get the same cutting performance as a Makita RT0701.

This is where we’ve been exploring brushless DC motors (BLDC motors).

One of the main advantages of BLDC motors is that they are much more efficient than a universal AC motor. Based on the suggestions from the company we are working with on developing the motor, it may be possible to use a 400 watt BLDC motor in place of a 1200-watt AC motor.

Additional advantages of using a BLDC motor include:

  • Higher efficiency and lower power consumption means less heat, which also means a smaller fan that creates noise
  • A wider speed range, allowing the router to be used more effectively at slower speeds
  • No need for replacing brushes, which also lowers noise caused from the brushes rubbing
Sample motor with BLDC

BLDC does have a few disadvantages. The first is the price. We expect a production-ready motor to cost 3-4 times more than a universal AC motor. Second is figuring out the additional complexity in understanding the motor control systems and feedback loops we can implement to ensure that we have steady and accurate speed control.

That being said we believe it is possible to keep the overall BOM cost overall low to keep the router affordable and we’ll be able to use some off-the-shelf designs and external expertise to optimize the speed control for the router.

We expect to receive some motor samples in the next week or two, and we’ll start conducting testing to determine if BLDC offers an effective option for the Sienci Router.

CO2 Laser

I just talked to Ikenna to get an update about the CO2 laser development. The CO2 laser development team just finished filming an update video today and plan to release it in the next few weeks. There will also be a survey to help us direct the development for the new product. We expect to start purchasing prototype parts in the next week and expect to have a working prototype at the end of January.

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?

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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.

Specifications

  • 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.

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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.

Pricing

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.

Production

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.

Ordering

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.

FAQ

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

November 2023 Production Updates

Hey y’all, Andy here with the Nov 2023 Production Updates. For past updates, make sure to check out our blog.

Some of the info we’re sharing here may refer to stuff we talked about in the October update, so feel free to read the last update if you haven’t yet.

This one is a super long update so…..enjoy.

We found a guinea pig

A few weeks ago (I was away), someone (I think Jen) saw a guinea pig run around in the parking lot and living under the shipping containers we have in the back. Eventually, we were able to capture it. What we suspect is someone let it go for some reason.

It appears that everyone has appointed it as the new CEO, and the team is looking for another guinea pig to keep it company (perhaps as the CTO?).

Moving

Getting stuff ready to move

As we mentioned in the last update, we’re moving! Moving has already started and we are working on putting in new plumbing and electrical. We should be getting a truck to move most of our stuff in the first week of November.

Because of the move, we may need to put shipping on pause for 2-3 days. We are working on planning this currently and we’ll put a note on the website when this will be the case.

There will be a video coming out soon so keep your eyes peeled!

LongMill MK2 Production

LongMill production continues to go smoothly, with most machines shipping out within a day or two, and the same day for Beginners Kits.

LaserBeam Production

LaserBeam also continues to move along smoothly. We are currently working on building a new batch and parts are trickling in.

Vortex Rotary Axis Production

The Vortex Rotary Axis continues to ship within a few days from stock. However, we are down to our last 30ish units. We are currently in production for the second batch, and expect to restock on another 300 units around the start of December. There may be a chance that lead times may increase once we run out of stock.

CO2 Laser

So it’s been a big passion project for Ikenna to develop a CO2 laser. For those who don’t know, Ikenna is the guy who developed the LaserBeam.

One of the main downsides of using diode lasers like the LaserBeam is that they are limited to how powerful they are, and thus limited to what and how thick of material they can cut. For context, while the LaserBeam offers a 7 watt optical output, most CO2 lasers can put around 40 to 100 watts of cutting power. A

CO2 lasers that exist on the market have some things we believe need to be addressed to make the technology more accessible to hobbyists. I won’t get into too much detail in this update, but look out for a video from Ikenna and Daniel soon that covers details about the project, as well as a survey coming to help us make some design decisions for the project.

Sienci Router

We’ve continued to work on the design for the Sienci Router. Thank you for everyone who participated in the survey to provide us feedback on the features and designs.

Split view of the casing with the bearing setup

One of the things we’ve been working on deciding over the last few weeks is the communication interface for speed control of the router, because at this current time, there are several different protocols used in hobby and industrial CNC controls, but the ones that we are addressing are RS485, PWM, and 0-10V analog.

GRBL, the firmware that the LongMill and many hobby CNCs run on, uses ATMEGA 328/Arduino hardware to do the motion control and run the functions of the machine. While this isn’t confirmed information, I suspect that GRBL-based machines primarily offer external control for peripheries like spindles and lasers using PWM because the hardware offers the support. PWM is basic, simple, and is generally fairly reliable for this type of application.

However, from my experience, while PWM is the primary interface for laser control, it’s rare to find on VFDs. More commonly, there is an analog voltage input, so in a VFD with a 0-10V range, sending a 5V signal would run the spindle at 50% of the rated speed. A lot of users plug their PWM signal into the analog input (which isn’t the proper way to do things), because the electronics in the VFD can sometimes average out the duty cycle of the PWM to a voltage. You can read a bit more about it in this previous article.

We also have been looking at different motor options and designs, some of which are here.

Different motors to test

Spring Loaded Anti-Backlash Nuts

We have now started manufacturing of the T12 Spring Loaded Anti Backlash nuts! Thank you to everyone who participated in our open beta of the T8 Spring Loaded Anti Backlash Nuts. We are also finalizing the design for the second iteration of the nut.

We are expecting production for the T12 nuts to take about 4 weeks. We’ll put out an update for everyone on the status and when they will be available for sale.

Roughing End Mills

We just received our first batch of 1/4″ Roughing end mills and are working on testing and checking the new design. For a little info, we wanted to make an end mill specifically designed for cutting guitar blanks. Cutting guitar blanks comes with a couple of unique challenges. The first is that guitar blanks are typically around 1.75″ thick. Most 1/4″ bits are usually designed to cut around 1″ to 1.25″ thick material, which means that most standard bits have trouble cutting through 1.75″ material from a single direction. The solution to this is to make a longer end mill, but longer end mills present a new challenge, which is that the longer the bit is, the more deflection is in the tool.

To get around this, we’ve made some specific design choices. First is to make the end mill stronger, we’ve gone with a 3 flute design, which means that there is more material in the flute area to give strength to the bit. The second is to add a serrated “chip breaker” edge to the flutes, which helps shear chips apart and prevent them from clogging up in the cut.

Overall we believe that this will be a great tool for guitar builders in general. And we also think that this will be a great addition to CNCers working with thicker materials.

We are currently doing testing and expect to have this available for sale in the next week or two so keep your eyes peeled!

Wanna see our video where we make a guitar body? Check out the video below!

AltMill

We are continuing to work on the AltMill. This project was put on pause since we had a lot of work we needed to get done in building our production and processes for the LongMill, as well as due to lack of space in our current workplace. Now that the LongMill has become more mature as a product and we are moving into a larger space, we feel its a great time to revisit the AltMill project. You can read about the initial launch here: https://sienci.com/2021/09/10/going-bigger-announcing-the-development-of-the-altmill-and-extended-versions-of-the-longmill/. We have just placed an order for the main linear motion parts and expect to have the rail manufacturing starting in the next week or two. Our plan is to build around 50 machines as a small test batch and build a larger batch based on interest.

For the uninitiated, the AltMill is our foray into larger format CNC machines using linear guides and ball screws. We are starting to work on forming the basis for upper-range CNC machines, while still keeping our core values of value and ease of use for hobbyist and small-scale production. These first units will have a 4×4 foot working area and offer an upgrade to the current LongMill. Prices are expected to be around $3000 to $4500 depending on the configuration.

We don’t have exact timelines yet, but I expect to see our first prototype units being built in the start of 2024.

SuperLongBoard

SuperLongBoard development continues to move forward. Chris will be putting out an update soon specifically for the SLB, so make sure to watch out for that. Progress feels like two steps forward, one step back sort of situation. Because the board is a lot more complicated than before, we’ve found that changing different parts of the board which depend on each other can cause things to change in other areas.

Additionally, the hope was that the second version of the controller would be our final version of the hardware, with features only needing to be implemented by updating the firmware. However, we’ve found a couple of mistakes and certain changes and improvements we can make to improve the board.

Brazil Trip

This past October, Leandro (our marketing manager) and I went to Brazil. Just for a bit of background, we were invited by one of the Canadian trade commissioners to do a trade mission in Rio Grande Do Sul, a southern province known for manufacturing. The goal of the trip was to establish relations between Canadian and Brazilian advanced manufacturing. We went to represent our company and the Canadian government and make connections with different organizations and companies in the region.

It was an amazing experience. One of the things that we got to do was visit and tour several large factories, including Randon, Tramontina, and Marcopolo, which are multibillion-dollar companies that employ tens of thousands of employees. There were a couple of takeaways that all the companies shared.

  • An emphasis on doing as much in-house as possible, with different departments that focus on making tooling, molds, robotics, and more for production, rather than outsourcing to other companies. Additionally, they have their own financial institutions, educational facilities, medical centers, and hospitals on the grounds where employees can get further support from their companies. I feel that this makes sense because of the scale of each company, and it is more efficient and effective to specialize their needs to the environment and employees that they have.
  • High volume production of commodity or commonly used items. Because all of these companies make products on such a large scale, they need to focus on making products that people use a lot of. For example, the Tramontina factory produces 20,000 pans and pots per day. Because they make so many and have the resources to optimize their manufacturing, they can make the pans cheaper than basically any company just starting out. This protects them against competition since other companies won’t be able to produce at the scale and efficiency they can.
  • The process for production and the departments are the same regardless of how big you get. In our company, we have people who work specifically in packing, engineering, QA, and customer service, to name a few. We need these different areas because it encompasses all of the different tasks that a company needs to do. In a larger corporation, it’s still the same, just at a larger scale. I think that once the company gets larger, the growth of certain departments, such as management and engineering, doesn’t grow linear compared to production and labor, because the products that are being made are the same, and you only need to scale certain areas to produce more.

I believe that there are many ways to take some of the things we saw and learned from this experience that we can apply to our own company as we continue to develop.

And also, the bbq in Brazil is incredible. Will return again soon!

Free Shipping for orders above $150USD to $200CAD to the US and Canada until Oct 31, 2023

Hey guys. As you might have heard from our last production update, we’re moving soon! To aid in our moving, we will be trying to sell as much stuff as we have in our inventory to reduce the number of trips we will have to take to bring everything to the new place.

This month, we are offering Free Shipping for orders above $150USD to $200CAD to the US and Canada. If you have over the threshold of items in your cart, you will automatically see a free shipping option at checkout.

We will keep this option available until the end of October (or until we run out of stuff).