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YOU CAN 3D PRINT A METAL LATHE AND FILL IT WITH CONCRETE

A lathe made of plastic and concrete that turns aluminium, for the price of a roll of filament and a bag of hardware.

by Chris Borge

FULL CAD BOM FIRMWARE DOCS

Workshop

Built with3D printing

difficulty
●●●●○
time
a weekend-plus
license
license not specified
repo
repo 0 stars

WHAT YOU’LL NEED

Videos
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COMPAREE VERDICT

Chris Borge designed a lathe that costs about as much as a good dinner and turns real metal. The body is 3D printed, then filled with concrete to add mass and dampen vibration. It works: in his video the tool peels aluminium curls off a spinning disc. The catch is scale. He is clear that this is for small parts, roughly under 10 mm, and the big disc was a torture test that stalled the motor. If you need to turn a pen part, a model engine part or a small spacer, this will do it. If you need to turn a 50 mm bar, it will not. You cut with a hand-held graver on a printed tool rest, an old technique the creator links guides for, so expect to practise on scrap. The second thing that will go wrong is alignment: if the spindle is not true before the concrete goes in, the error is permanent. The files are complete, the licence permits commercial use, and the cost is honest. This is not a replacement for a bench lathe, but it is a real lathe that fits on a desk.

GOOD TO KNOW

  • —45 files (STL and STEP) on Printables, plus a bill of materials and a build guide.
  • —Licence is CC BY — you can build and sell these.
  • —The creator says it is meant for small parts under about 10 mm diameter; the large disc in the video was a torture test.
  • —Cost estimate from the creator is 100-150 AUD (66-100 dollars) including basic tooling.
  • —No firmware — this is a manual lathe driven by a motor, not CNC.
  • —You will need to source and mix concrete, align the spindle and set up the tool rest yourself.

Parts to buy

9 items

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

  • 20 mm ER-collet spindle and colletsFind
  • Two 32204 bearingsFind
  • Small motor and speed controllerFind
  • 2060 and 2020 aluminium extrusionFind
  • GT2 pulleys and beltFind
  • M8 coupling nuts and threaded rodFind
  • M4 T-nutsFind
  • Heat-set inserts and boltsFind
  • Super glueFind

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Can I build this?

PrintThe entire body, bed, headstock, tailstock, tool rests and die holder — less than 1 kg of PLA according to the creator
BuyA 20 mm ER-collet spindle and collets, two 32204 bearings, a small motor and speed controller, 2060 and 2020 aluminium extrusion, GT2 pulleys and belt, M8 coupling nuts and threaded rod, M4 T-nuts, heat-set inserts and bolts, super glue, about 1 kg of PLA and a bag of pre-mixed high-strength concrete - see the parts sourcing document linked from Printables
Tools3D printer, soldering iron or insert tool for threaded inserts, drill, spanners, mixing bucket for concrete, a graver for turning
SkillsIntermediate 3D printing, basic metal threading and tapping, patience for alignment — a lathe has tight tolerances and you will be shimming parts by tenths of a millimetre
TimeA weekend to print and assemble, then another few hours to fill with concrete, cure, and tune alignment — plan for two weekends
CostModerate — creator's estimate is 66-100 dollars (100-150 Australian dollars) including basic tooling; he used a salvaged motor and says the collets are the one part worth buying the best you can afford
SafetyA lathe throws chips and can catch the tool: wear eye protection, do not wear gloves (the creator's explicit warning - they can be pulled in), and keep hands and clothing clear of the spinning work. Keep the small 1000 rpm motor: the creator says it simply stalls when the hand-held tool catches, and a bigger motor would make this dangerous. Concrete dust during mixing irritates lungs - mix outdoors or wear a mask.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

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Start here

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

  1. 1.Download the 45 STL and STEP files from Printables (The page includes a bill of materials and a build guide)
  2. 2.Print the body parts in PLA — total filament is under 1 kg(The lathe is 44 cm long but split into parts; check the largest STL against your printer before you start)
  3. 3.Source the motor, bearings, belts and fasteners from the BOM(The creator's cost was 100-150 AUD (66-100 dollars) including basic tooling)
  4. 4.Assemble the frame, then mix and pour concrete into the cavities(Let the concrete cure fully before mounting the motor or spindle)
  5. 5.Mount the spindle, motor and tool rest, then check that everything runs true(This is the step that will take longest — a misaligned lathe chatters and leaves poor finishes)

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 creator is clear this is for small parts under about 10 mm — if you need to turn larger stock, this lathe will not have the rigidity or throw.
  • Alignment matters: if the headstock and tailstock centres do not line up, parts come out tapered. Check alignment before the concrete goes in, and learn graver technique on scrap — the tool is hand-held on a rest.
  • The concrete adds mass but also locks in any errors — if you pour before checking that the bed is flat and square, you cannot easily fix it later.
  • The lathe throws chips - wear eye protection, no gloves (the creator's warning), and do not fit a big, powerful motor: the small one stalling is a safety feature when a hand-held tool catches.
  • The parts document is about 90 percent done: bearings and the spindle are specified exactly, but the motor is deliberately generic (the creator used a salvaged motor and encourages that), so you have to make your own motor mount plate and choose pulleys to suit it.
  • Concrete dust during mixing irritates lungs — mix outdoors or wear a mask, and do not pour indoors without ventilation.

Can this turn steel?

The video shows aluminium, but the creator's parts document says he also turned steel (at about 2000 rpm, brass and aluminium at about 1000 rpm, changing speed with the pulleys) and got a nice surface finish. Keep to small parts and light cuts with the graver: this lathe is not designed for heavy steel work.

How rigid is concrete compared to cast iron?

Concrete is less stiff than cast iron but much better than plastic alone. The mass damps vibration, which is what matters for finish. A cast iron lathe will be more rigid, but this costs 100 dollars and fits on a desk.

Do I need a CNC controller?

No — this is a manual lathe. You hold the cutting tool (a graver) by hand against a printed tool rest, so there is no carriage, handwheel or firmware; the only electronics are the small motor and its speed potentiometer.

What is the maximum part diameter?

The creator says the design is for parts under about 10 mm. The large disc in the video was a torture test, not normal use.

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Discussion1

FROM THE COMPAREE TEAM

The creator says it is meant for parts under 10 mm, and calls the large disc in the video a torture test that stalled the motor. What is the smallest part you would actually want to turn on this?

CompareeTEAM7d agoedited

Practical notes from our verification: the 45 files on Printables are 44 STL parts for printing plus one STEP model for modification. Parts sourcing is in a linked Google Doc (the creator calls it 90 percent done), and the main body build guide is a separate linked document, so check both before ordering. The creator's own estimate is 100-150 Australian dollars including basic tooling, and the whole printed shell uses less than 1 kg of PLA. The concrete step is not reversible — once poured, any alignment errors are permanent, so dry-fit everything twice before mixing. The files went up in October 2024 alongside a video that now has over 930,000 views; there is no GitHub repository and no firmware, because the lathe is turned with hand tools on printed tool rests and a small 1000 rpm printer motor. 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.

Chris Borge

Chris Borge designed Open Lathe V1 to prove that a lathe does not need cast iron to turn metal — it needs mass and stiffness, and concrete delivers both. The design uses less than a kilo of filament and costs about 100 dollars.

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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.
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