Homemade ACME Tap


I’ve been working on a new CNC mill and I’m using ACME rods to drive the x and y axis. An ACME rod has about half the turns per inch when compared to a standard rod and allows the machine to move twice as fast. The only downsides are ACME couplers and nuts are expensive and difficult to make without $40 ACME taps. I stumbled onto Michael McKinley’s site and decided to try making a  homemade tap. He used a drill press and a file for his. I wanted to spice it up and used a Dremel and belt sander, it took 30 minutes and saved me a lot of money. Best part this trick can be used on any threaded rod as long as the material you are cutting into is soft. Michael’s site has a lot more detail on the angles of the flutes and how to cut the reliefs. I winged it since I was only cutting delrin plastic. I might fine tune it at a later date if I want to try some soft aluminum.

In the picture above I colored the flute of the tap to show it more clearly.

One Comment on “Homemade ACME Tap”

  1. Natool says:

    What a good find. It’ll definitely save money.

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