Making wooden gears

29 Nov

I wanted some small wooden gears to decorate a steampunk costume. Nothing fancy, they don’t have to do anything.

Four different programs are needed to turn my idea into a chunk of machined wood:

The starting point is the very useful (and cheap) Gear Template Generator from, which lets you choose all sorts of parameters for your gear. If you just want to print it out on paper, then the web-based program is free, but I bought the program ($26) a couple of years ago and that lets me export out a .dxf file which my cad software can eat.

The .dxf files (one per gear size) get imported into the CAD (computer aided design) software. I use CAD X11, which is somewhat funky but does the job and is fairly cheap.

After that there’s yet another program, this time it’s a CAM (computer aided manufacturing) program, where I map the lines on the diagram into movements of the cutter. I use CAMBAM which does the job nicely.  I tell it “I want to cut around the inside of this triangle, with a cutter of X diameter, cutting at speed Y, in passes Z millimetres deep” and it turns it into the truly strange NC (numerical control) data format that many computer controlled machines use.

One last program, Mach 3, reads the NC file and wiggles the motors on the computer controlled cutter to make it follow the pattern I want.

  • Here’s the computer controlled cutter, with a piece of 3mm MDF (fake wood) clamped in place to cut some mounting holes.

  • Measuring the how high off the surface the cutter is, using a pack of cards and a vernier caliper. The wood is bolted down, now.

  • Many layers of sound-proofing are needed when the little trim-router gets going.

  • The Mach3 software steps through the hundreds of lines of  “go to …”, then “follow curve …”, “lift up by …” etc. You can see the pattern it has to cut at top right.

  • And after an hour (it’s a very slow machine), it’s cut out some gears and a generated a lot of sawdust. Time for the vacuum cleaner.

  • Fresh off the cutter the gears are pretty rough – with fuzzy edges and bits to remove.

  • A quick zap with the belt sander cleans them up nicely.


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