Acme Thread Gage

A set of gages for measuring acme threads, often found on machine tools including 3D printers. Commercial gages exist but are a bit pricey. Files included here for 3D printing as well as laser-cutting.

LASER-CUTTING

• This is my go-to tool for making things like this; it's super fast and accurate 1/16" (1.5mm) acrylic will work great, but chipboard or even paper will work too in a pinch
• For a fancy touch, fill in the engraved numbers with some paint

3D PRINTING

• STL files include single thread pitches so you can just print the one you want
• Gages are 1/16" (1.6mm) thick, which isn't very robust but will make printing quick and measuring easier
• Note! If the gages look really small in your 3D printer program, it's probably because the files are in inches but STLs are in millimeters. Your slicer should be able to scale them for you (each one is 2" long)

INKJET/LASER PRINTER

• You can also just print out the letter-sized PDF file, trim with an x-acto, and measure that way!
• Be sure to check that it is printed at 100% size or you'll have a bad time!

Please note! While these have been designed accurately to the published specs, your printer/laser-cutter will likely change the shape a bit, either bigger or smaller. The gages should still work, but if you're measuring something and it must be super accurate, you'll probably want to go with a commercial set. (Of course, if you're making something that important then spending $40 on some measuring tools is probably a no-brainer)

TO CONNECT TOGETHER
Divide gages into two groups, one with 6 and one with 5. Using a bolt/nut (listed below), fasten together so you can pull out individual gages but tight enough so they don't come apart.

This is totally optional! It just makes it a nice set that won't get lost around the shop.

WITH BOLTS

• Stainless steel hex bolt
  • 2 @ #6-32 x 1/2"
  • https://www.mcmaster.com/92949A148
• Stainless steel nut
  • 2 @ #6-32
  • https://www.mcmaster.com/90730A007
  • OR...
  • https://www.mcmaster.com/90101A007

WITH BINDING POST

• Stainless steel binding post
  • 2 @ #6-32 x 1/2"
  • https://www.mcmaster.com/99637A520
  • holes in the gages will need to be modified to fit the barrel; either change in the file or modify with a drill
  • may require grinding down the barrel a bit so that it fits right