Prep for your AltMill


So you just purchased your AltMill…now what? While you’re waiting for your machine to show up, you can:   

  • Buy a sheet of 4’x8’x¾” MDF for your table, and think of how you would hold down your projects during cutting  (aka workholding)  
  • Source your own spindle, if you are not getting the Sienci Labs Spindle Kit 
  • Grab cutting tools for the types of projects you’re interested in making
  • Figure out your dust collection system 
  • Determine what computer you would need  
  • Familiarize yourself with CNC software and determine a set of software programs that suits your CNC needs
  • Clear a work space in your shop or garage for the machine
  • Join our Facebook group and Forum for community-driven discussion and inspiration!
  • Once it has shipped, gather your assembly tools: a set of metric Allen keys, standard bits, and a drill 


The AltMill comes with a sturdy frame that you can mount a table surface and wasteboard to. The ¾” thick 4’x8’ MDF sheet (purchased separately) will act as our table surface and will attach onto the frame with screws. Full instructions can be found here. The wasteboard is mounted on top of the table surface, and can be fully customized to suit your application, allowing for various workholding options to be implemented. Here are some common examples of workholding methods used in consumer-level CNCing: 

Using clamps

  • T- tracks with MDF slats
  • Grid of 5/16” threaded inserts, counterbored on a second MDF sheet

Using adhesives

  • Painter’s tape with CA (cyanoacrylate) glue, on a second MDF sheet 

Front view of AltMill with MDF table, T-tracks and MDF slats


For the AltMill, we do recommend using our Spindle Kit as it has been tested thoroughly under our specifications, and the included VFD has been pre-programmed. It is an air-cooled spindle, and is rated at 1.5KW, 110V which can run off North American household outlets. If you are looking to upgrade to a higher power spindle, we recommend keeping the spindle power between 1.5-3.5KW. If you reach 2.2KW or above, you will need to install extra 220VAC wiring to support this. Furthermore, ensure that the spindle body is 80mm or smaller in diameter so that it could be mounted onto the AltMill as-is or with your own shimming. The AltMill comes with an 80mm spindle mount, whether you purchase the Spindle Kit or not.   


AltMill 1.5KW 110V spindle

Cutting Tools

There is a vast variety of end mills and specialized bits available for different use cases, from carving signage to cabinetry pieces. The video below explains the basic features of a cutting tool, and highlights the differences between common types of tools.


Further reading on the recommended tools for specific project types can be found here.

Dust Collection 

Having proper dust collection for you CNC machine will:

  • Keep dust out of the air and on sensitive machine components
  • Remove chips and debris out of the cutting areas, reducing the chance of rubbing or burning
  • Reduce cleanup after your job is completed

The general specifications for a dust collector suitable for the AltMill are as follows:

  • 1-3hp
  • Single, double or triple bag
  • 4” diameter hose (or you can source/make your own adapter) 
  • At least 600 CFM rated flow rate

Also known as the vacuum attachment, the dust shoe is connected to a hose leading to the dust collector, sucking up debris on the work surface. If you are choosing a different dust shoe for the machine, here are some factors to consider: 

  • Spindle size
  • Hose size/suction power
  • Z-axis adjustability of the dust shoe 


AltMill 4″ Dust Shoe

Work Space

Detailed drawings for the AltMill are shown below, illustrating the table and machine dimensions. Ensure that you allocate at least 6’x12’ of space for the machine build.

Top view of AltMill showing width and depth dimensions, PDF found here: AltMill Key Dimensions


Front view of AltMill showing table and machine height, PDF found here: AltMill Table Leg Dimensions