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The SuperLongBoard 5xHAL is a next-generation 32-bit controller for the LongMill, open source for other CNCs as well.

Look forward to everything that the original LongBoard (typical grbl) can do… plus:

  • Faster movement and jogging speeds
  • Quieter motors
  • CNC status lights with support for external lighting
  • Safe E-stop depowers motors and disables accessories
  • Programmable action buttons to suit your workflow
  • Faster probing and higher sensitivity with touch plates
  • Higher level spindle control using RS485**
  • Smoother and faster laser motion and engraving
  • Independant 4th/Rotary axis output for simultaneous 4-axis cutting
  • USB-C and Ethernet connectivity to computer with extensive shielding and onboard ferrites to improve communication reliability

To know more, check out our FAQs below ↓ and our rapidly expanding SLB documentation!
Also see more in our mega blog post, recent updates, or Livestream.

*Controllers are now shipping as of March 2024! Please note that any SLBs ordered now will be backordered, and expected to ship in June 2024.
**Huanyang v1 and P2A, and H-100 currently tested to work out-of-the-box. More to be added in the future.

Available on backorder


Supercharge your CNC

The SuperLongBoard, or “SLB”, is an advanced, next-generation, plug-and-play, CNC controller for ALL GENERATIONS of the LongMill. The SLB allows your CNC to run faster and more reliably. We believe the SLB is the most significant upgrade in functionality and performance for all LongMills, past and present.

Each order will comes with:

  • The SuperLongBoard in a protective aluminum enclosure
  • Detached E-stop with customizable action buttons
  • 2.5m E-stop cable
  • Mounting flanges for four, screw size #4 to #8
  • Mounting bracket, specific to use on the Y-axis of a MK2 (not MK1)
  • *You’ll need to provide your own minimum 24V 10A power supply, we supply these and all past LongMills have shipped with one

The SLB creates a platform for our company to continue developing and bringing advanced features and improvements to the LongMill and other CNC machines in the future.

There are way too many updates and changes we’re bringing with the SLB to mention all of them, but we’ll continue to show functionality and answer questions as we get closer to production. For company updates in the meantime, keep an eye on our Blog or get news directly to your inbox by signing up.


Q: When will the SLB ship?

A: The first round of SLBs have already shipped. Back-orered SLBs are expected to start shipping late May early June. We will continue to post updates on our Blog. To get news directly to your email inbox, feel free to subscribe to our mailing list.

Q: Can the SLB work on my LongMill?

A: The SLB is compatible with ALL LONGMILLS. No matter what size, generation, or version you have, the SLB will plug and play with existing LongMill hardware of all generations with minimal settings changes. We believe this will be one of the most substantial upgrades any LongMill can have, past or present!

Q: Will the SLB come default with the LongMill in the future?

A: Yes, starting with our new batch of MK2.5 LongMills the SLB will now ship standard with the machine. This also comes with an associated price increase to reflect the additional value we believe the SLB provides.

Q: Will the SLB work with my CNC?

A: If it’s a LongMill or AltMill then definitely it will. Otherwise, your CNC should be supported so long as it’s a typical hobby CNC setup with open-loop Nema 23s. As we roll out the SLB we’ll begin hearing back on other successful configurations and update this ‘Answer’ appropriately, since otherwise we can’t provide a definitive guarantee other than to say that it’s very likely to work for most hobby CNCs. Other machines that have been proven to work so far: Onefinity.

We’ve earnestly done our best to ensure the SLB would be ideal for any typical setup since the inspiration for the SLB came from trying to take things that are normally only available on more expensive and ‘closed’ boards and bring them into the open source domain and at a more affordable price for the benefit of as many hobbyists as we could. This means that although you will need to change certain settings to match your specific setup,the SLB will support a range of machines and accessories including 5/24V limit switches, touch plates, tool length sensors, laser diodes, external 4th axis, and more.

Q: What about if I want to use higher voltage or external motor drivers?

A: We do currently have another version of the SLB in the works that we’re calling SLB EXT since it’ll support much higher voltage and external motor drivers for closed loop support as well. This will extend even further SLB support for a broader range of machines and setups closer to production-level. This board will be what powers our AltMill CNC and you’ll be able to see more updates about it on our blog as we begin making deliveries.

Q: How can I know if the SLB is right for me?

A: There are many other offerings on the market that come with a wide range of features, simply put the choice between these will always come down to budget. If you don’t think you need the features offered by the SLB then it’d make more sense to spend less money. In this case consider getting a more typical grbl board or some of the newer x32 hobby CNC boards that might require more DIY setup time for wiring or programming. For instance the Blackbox x32 has the benefit of a direct wireless connection but less extensability. If instead you feel like you want to pull all the stops to support a higher-end CNC or use more advanced features then you might want to increase your budget and look into a Centroid, UCCNC, or Mach setup. We believe though that we’ve done our best to match the SLB up with the mid-level hobby CNC community where it makes sense to spend $150-200 on a controller to really unlock all the capabilities you’d be looking to expect out of your $1000-4000 CNC.

Q: Is the SLB open source?

A: Yes, the SLB, firmware, and related software like gSender will be released open source. This may come at a later date when we feel that our designs are finalized and should be available soon on our Resources pages.

Q: Will the SLB support external drivers?

A: Although we will support an external A-axis driver support to allow full 4-axis motion with the Vortex Rotary Axis, the SLB will not have support to external drivers for the X, Y, and Z axis.

Q: Will the SLB support accessories like the Vortex Rotary Axis, AutoZero touch plate, or LaserBeam?

Yes, the SLB will support all of our existing accessories for the LongMill, as well as opening up additional improvements and functionality to accessories, such as improved laser motion control, fully independent 4th axis control, and improved speed and sensitivity on touch probes and plates.

Q: Will the SLB support toolchangers?

A: The SLB does come with the hardware to support the IO for a toolchanger, such as relay control and tool length sensor inputs. However, we have not yet tested the functionality for a tool changer with the LongMill.

Q: Does the SLB come with a warranty?

A: The SLB comes with a standard 90-day warranty once it arrives at your door against all manufacturing defects. For further conditions, please check out the warranty tab on this page.

Details for returns can be found on our store policy page.

Additional information

Weight 5 lbs
Dimensions 6 × 8 × 4 in


The SuperLongBoard comes with a 90-day warranty starting at the time of arrival to the customer against manufacturing defects. Those 90 days are also covered for use of the board as long as it uses:

  • A correctly-specc’d and high-quality power supply like the 24V 10A or 24V 12.5A ones we’ve shipped with our LongMill CNCs
  • Tested and approved firmware developed by Sienci Labs without modification to the source code

Please note that power supplies with the incorrect output voltage and/or current may damage the board. We also strongly recommend using default or recommended settings for the SuperLongBoard. Damage caused by incorrect settings may not be covered by warranty or assessed on a case-by-case basis.