YOU CAN BUILD A CNC MACHINE THAT CUTS ALUMINIUM, AND THE PLANS ARE FREE
A CNC machine made of aluminium extrusion and steel plate that will cut metal — and every file you need is published free.
WorkshopOpen-hardware
- difficulty
- ●●●●○
- time
- several weekends
- license
- license not specified
- repo
- repo ACTIVE239 stars
●●●●○ · several weekends · license not specified · 239 stars · repo ACTIVE
WHAT YOU’LL NEED
- 3D printer + filament — printable parts — files are in the repo
Partner
COMPAREE VERDICT
IndyMill is an open-source CNC mill designed to cut aluminium without costing as much as a car. The frame is aluminium extrusion bolted to 6 mm steel plates, with ball screws and linear rails doing the precision work — that rigidity is the entire difference between a machine that can handle metal and one that only manages foam. It runs on Nema 17 or Nema 23 steppers and has been tested cutting wood, MDF, acrylic and aluminium with a 500 W spindle. The design scales by buying longer profiles and rails. Everything needed to build it is in the repository: STEP files, STL files, dimensioned plate drawings and a complete spreadsheet BOM. The author also published a four-part video build series. The single thing most likely to go wrong is underestimating the machining required — those steel plates arrive as raw stock and you will need access to a drill press, taps and patience. The repository carries no licence file, so the legal status for commercial builds is unclear. If you want a CNC that can actually mill metal and you have the tools to fabricate the frame, this is one of the few genuinely open designs that will get you there.
IN THE REPO
NOT IN THE REPO
- —STEP and STL files for all printed and machined parts are in the repository
- —Dimensioned drawings for every steel plate are provided as PDFs
- —Full parts list published as a spreadsheet
- —Four-part video series covering the entire build exists on YouTube
- —No licence file in the repository — files are published free but legal status for commercial use is unstated
- —Author sells an optional paid PDF guide and some parts through a separate store — those are not included in the free repository
Can I build this?
This build involves mains voltage — for adults comfortable with electrical work only.
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Partner · KickstarterHeyGears G1: 10M+ colors and transparent parts in one print, plus UV printing on flat objects. Figures, parts and labels — no painting.
Videos
IndyMill - Part 1 - Assembly
First of a four-part series covering the entire build, from unpacking parts to the final test cuts
Gallery
Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the repository README and watch Part 1 of the video series (Get a sense of the full build before buying anything)
- 2.Download the parts list spreadsheet and steel plate drawings (Work out which size you want to build and what the total cost will be)
- 3.Source the steel plates — either cut and drill them yourself or have them fabricated to the dimensioned drawings(This is the step most people underestimate — raw plate needs holes drilled and threads tapped)
- 4.Order extrusion profiles, ball screws, linear rails and steppers to match your chosen size(The design scales by simply buying longer rails and screws)
Resources
Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.
KNOWN ISSUES
- The steel plates arrive as flat stock — you need to drill all the holes and tap threads yourself, or pay a workshop to do it. That is the hidden time cost.
- No licence file in the repository means the legal terms for commercial use are unclear — if you plan to sell parts or offer milling services, confirm with the author first.
- The author sells a paid PDF guide and parts through a separate store — the free repository has everything you need, but do not assume the paid guide is included.
- A 500 W spindle works but is not fast — cutting aluminium will be slow and you will need to tune feeds and speeds carefully to avoid breaking endmills.
- Ball screws and linear rails from cheap suppliers can have slop or poor tolerances — that will show up immediately when you try to mill anything precise.
- The repository includes STEP files but no ready-made Gerber or pre-drilled plate files — you are doing the machining work yourself.
Can I build this without access to a drill press?
Not realistically. The steel plates need precise holes drilled and threads tapped — a hand drill will not give you the accuracy needed for the frame to be square.
What size endmills and speeds should I use for aluminium?
The project does not prescribe specific tooling, but a 500 W spindle running at low RPM with a 3–6 mm carbide endmill and shallow depth of cut is the starting point. You will need to tune feeds and speeds yourself.
Is this machine rigid enough to replace a Haas or other industrial mill?
No, and the project does not claim that. The stated goal was to make CNC machining accessible and inexpensive, not to build the most heavy-duty machine possible. It will cut aluminium, but slowly and with care.
What licence is this released under?
The repository contains no licence file. The files are published free, but the legal terms for modification, redistribution or commercial use are unstated.
Community builds
No community builds yet — be the first, we feature the best ones.
Discussion1
FROM THE COMPAREE TEAM
The frame is aluminium extrusion and 6 mm steel plate — no wooden base, no compromise on rigidity. What would you cut first if you built one?
Nikodem Bartnik
Nikodem Bartnik is a maker and engineer who wanted to bring CNC machining within reach of anyone with a workshop. The goal was not to build the most heavy-duty mill in the world, but one simple and inexpensive enough that it would actually get built. He published the entire design free and documented the build in a four-part video series.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM9d ago
Practical notes from our verification: the repository contains everything claimed — STEP files, STL files, dimensioned steel plate drawings and a full spreadsheet BOM — but there is no licence file, so the legal status for commercial use is unclear. The author runs a separate paid store selling an optional PDF guide and some parts; those are not part of the free repository and we have not reviewed them. The four-part video series is on YouTube and covers the entire build from parts to first cuts. The single biggest surprise is that the steel plates arrive as flat stock — you will need to drill and tap every hole yourself, or pay someone to do it. That is the hidden time cost no one mentions.