A Small Tapping Block

A few days ago, I mentioned to Machinist Mike about tapping a ton of holes in a tooling plate I have been planning on making. He showed me this great little tapping block he made and regularly uses. It was made of 2 inch steel round with 9 holes for #0 to 1/2″ taps, which acts as guides to keep the tap perpendicular to the surface of the part. He graciously gave me a copy of his solid model to build my own.

I built a smaller version with some scrap aluminum I had laying around. It has 5 holes for #0 to 1/4″ taps, which should cover 95% of tapping on projects with a Sherline or a benchtop mill. If I need bigger, I could always make another one. If you’d like to make your own, the drawing is shown below. Measurements are referenced from the smallest hole.

UPDATE: To get into some tighter spots, the drawing now shows all of the guide holes closer to the outer edge of the block, but still with enough meat to hold up well for a while.