The AltMill represents the pinnacle of hobby CNCing, bringing industrial level technologies to a price point and ecosystem for both beginners and advanced users.

General Specifications

  • Rigid frame and linear motion design using HGR15 linear guides and ball screws on all axis mounted to a custom-designed, machined aluminum extrusion
  • Closed loop stepper motors for over 600IPM
  • Support for 65mm and 80mm spindles and routers
  • Approximately 49″ by 49″ inch working area with a max z-height of 5.5″
  • Footprint of 59″ wide and 62″ deep
  • Inductive sensors for homing included
  • Sturdy metal legs with the ability to add 4ft wide shelving underneath

News and Updates

  • Time to grow the team at Sienci Labs

    As we talked about in the blog post “Everything You Need to Know About the AltMill”, the launch of this new machine represents a pretty big shift in our company,…

  • April 2023 Production Updates

    April fools LongMill MK2 LongMills continue to ship out as usual. We received another batch of controllers after being out for another few days. Batch 9 production continues and we…

  • The AltMill CNC Is Open for Preorders!

    We’re thrilled to announce that the AltMill CNC is now officially available for preorders! Don’t miss your chance to secure yours by visiting our website!

  • 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…

  • 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…

  • March 2024 Production Updates

    Hey guys, it’s Andy again with March 2024 production updates. I am currently writing this in China, where I am taking a bit of a “work-acation” but also to visit…


Q: Will the AltMill come with the SuperLongBoard?

The AltMill will come with a specialized variant of the SLB which allows for use with a higher 48V power supply and with external driver support. Features that the SLB comes with, such as independent 4th axis control, RS485 protocol, and more, will be shared between the AltMill and LongMill.

Q: What’s the difference between the AltMill and the LongMill

The AltMill was developed to be a higher-performing machine compared to the LongMill. Our main design goal was to create a machine that had the best possible value for dollar at a higher level and pricepoint.

  1. The AltMill is larger, with a working area of 48×48 inches, whereas the LongMill comes in 12×30, 30×30, and 48×30 working areas.
  2. The AltMill is more powerful, allowing higher rapid speeds and deeper cuts. For context, the AltMill will allow for speeds over 600 inches per minute versus 160 inches per minute.

Q: What software does the AltMill come with?

The AltMill works with our free gSender software for controlling your machine. Any software that works for CAD/CAM with the LongMill also works with the AltMill.

Q: What else do I need to provide with the AltMill?

Besides the standard items we sell (machine, legs, spindle) , users will need to provide their own wasteboard (we recommend 3/4″ MDF), computer, and end mills.

Q: What accessories does the AltMill work with?

The AltMill will support accessories such as the LaserBeam, Vortex, and both the Autozero and regular touch plates.

Q: Will the AltMill come in any other sizes besides the 48×48 inch working area?

For the time being, we are focusing on developing and maturing the design of the 48×48 size. However, a successful launch and release of the AltMill 48×48 does pave the way for larger machines that could cut full sheets of wood, or smaller machines dedicated to cutting metals. We believe that the AltMill isn’t just a machine, but a new platform we can build upon for new form factors.

Q: What is the footprint of the AltMill?

The width of a fully assembled AltMill with our table legs is approximately 59″ wide and 62″ deep. Users should allow for a few inches of extra space on each side.

Q: What are the power requirements for the AltMill?

The AltMill comes with a 48V10A power supply, which can supply 500 watts of power. Users should dedicate additional power based on the spindle they choose to use, which can range from 1.5KW and above. This may require having two or three available breakers, or 220V available for your spindle.

Q: Can I add a toolchanger to my AltMill?

At this time, we do not have development or plans to release a toolchanger, but the AltMill and it’s hardware and electronics offer inputs and outputs to allow aftermarket toolchangers to be added by the user.

Q: Can I modify, update, trade-in, my LongMill to a AltMill?

No, because of the significant differences between the LongMill and AltMill, there is no path for upgrade or modification. Additionally, we currently do not have the infrastructure to support trade ins for the LongMill.