Hi, I'm going to make a tapping block (chunk of metal with holes to help align hand taps), and I thought I'd try and learn a bit about material selection, hardness, and plating at the same time.

The goal is to make something that can get thrown around in the shop a bit without getting dinged up and also won't rust.

Right now I'm planning on making it from 4140, heat treating to RC30 or 40, and applying electroless nickel plating. Is this overkill?

Overkill? Yes. I say overkill, because I find myself drilling new guide holes in the block all the time. I choose to only drill the holes I need at the time I needed them. I think it makes the block easier to use than just a generic block full of holes.

You can make an effective tapping block from aluminum, as long as the smooth part of the tap can ride on the wall of the hole. I've tapped thousands of holes using my simple aluminum block, to speck. Dont get me wrong, hardened steel would definately be a better solution, but for the effort involved, it's not worth it in my mind. Plating? As long as you don't plate the insides of the holes. There would be alot of plugging involved.

Just my 2 cents.

Paul

Damn I think at tapping block at all is over kill, a 1-2-3 block to check if its going in straight is very easy and effective.

In the good old days you just lined it up by eye :) .

In the good new days I put it in the CNC and write a two line MDI program.