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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.

by Nikodem Bartnik

FULL CAD BOM FIRMWARE DOCS

WorkshopOpen-hardware

Built with3D printing

difficulty
●●●●○
time
several weekends
license
license not specified
repo
repo ACTIVE250 stars

WHAT YOU’LL NEED

Videos
1
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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 the steel plates: you need a laser-cutting service that can cut the small holes from the DXF files (or buy the plate kit), and then taps and patience for the threads. 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.

GOOD TO KNOW

  • —STEP and STL files for all printed and machined parts are in the repository
  • —Every steel plate is provided as a DXF file (in mm) ready for laser cutting, with preview images
  • —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

Parts to buy

7 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Aluminium extrusion profiles (2080 and 2040)Find
  • 6 mm steel plates laser cut from the DXF filesFind
  • Ball screwsFind
  • Linear railsFind
  • 500 W spindleFind
  • Controller boardFind
  • FastenersFind

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Can I build this?

Print3D-printed ball-screw blocks, nut holders, a Z-axis bearing holder, a limit switch holder and optional ball-screw covers — STL and STEP files provided
Buyaluminium extrusion profiles (2080 and 2040), 6 mm steel plates laser cut from the DXF files, ball screws, linear rails, Nema 17 or 23 steppers on X/Y and a Nema 23 on Z, 500 W spindle, controller board, fasteners
Toolstaps and a tap wrench for threading the steel plates, hex keys, spanners, soldering iron, a laser-cutting service (or the pre-cut plate kit) and a CNC controller
Skillsintermediate mechanical assembly, tapping threads in steel plate, wiring stepper drivers, CNC controller setup and tuning
Timeseveral weekends — frame assembly and wiring can be done in a weekend, but machining the plates and final tuning will take longer
CostHigh budget, dominated by the linear rails, ball screws, steel plates and spindle; price the BOM spreadsheet for the size you build, as the project does not publish a total
SafetySpindle work throws metal chips — safety glasses and a chip guard are not optional. Mains-voltage spindle wiring. Keep hands clear of the spindle and moving axes during operation.

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.

Videos

IndyMill - DIY CNC Machine #2 Assembly

Part 2 of the four-part build series (Parts, Assembly, Electronics, Final Test) — the frame and axis assembly. Start with Part 1 for the parts overview.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the repository README and watch Part 1 of the video series (Get a sense of the full build before buying anything)
  2. 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. 3.Get the 6 mm steel plates laser cut from the DXF files in the repository, or buy the plate kit(Send the DXF files to a laser-cutting service that can cut the small holes, or buy the plates pre-cut from the author's store; you still tap the threads yourself.)
  4. 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 are laser cut from the DXF files in the repository, holes included — make sure your cutting service can do small holes, or buy the plate kit from the author's store. Tapping the threads is still on you.
  • 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 DXF files for every steel plate, ready to send to a laser-cutting service, plus Eagle files for the IndyShield controller board — you only need to tap threads and assemble.

Can I build this without access to a drill press?

Mostly yes. The plates are laser cut from the DXF files with all holes included, so you are not drilling them by hand; you mainly need taps for the threads and basic hand tools.

What size endmills and speeds should I use for aluminium?

The project does not prescribe tooling or feeds and speeds. It says the machine cut aluminium with a small 500 W spindle; start conservatively with light cuts and tune for your spindle and endmills.

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?

CompareeTEAM1mo agoedited

Practical notes from our verification: the repository contains STEP and STL files for the printed parts, DXF files for every steel plate, Eagle files for the IndyShield board, and a BOM as PDF and XLSX, but there is no licence file, so the legal status for commercial use is unclear. The plates are laser cut from the DXF files with the holes included, or you can buy them pre-cut from the author's store; the store also sells other parts, and an optional paid PDF build guide is offered separately. The four-part YouTube series covers parts, assembly, electronics and a final test. Check motor compatibility before ordering: X and Y take Nema17 or Nema23, but the Z axis only fits Nema23 without redesigning a plate. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

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.

GitHub

Star the project on GitHub

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.
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