G'day everyone,

I think there is a time where every hobby machinist will find that they need to make a custom thread tap, and that day has come for me. I need a large M20 tap with a fine pitch, much finer than the ones commonly sold. M20 usually comes with a 2.5 or if you are lucky 1.5mm pitches, but for an upcoming project, space is tight, and I need a tap with fine threads.

Now M20x1.0 isn't exactly an exotic thread (such as M5.5 x 0.5 or M7.9 x 0.6 which I have taps for) and they are sold online. Roughly $20 for a Chinese Tap or $50 plus shipping for a German made one.

However it is a lot to pay for a tool that I am only going to use once, so I thought it would be a nice challenge to try and make it myself.

I have made one or two before (M7.5x0.7) but none which were designed to cut steel. So I'll need to be very careful about making this, and including the proper cutting geometry and relief angles.

I will also need to carburize the steel in order to harden it. I hope you enjoy the video.

#machining #DIY

Custom Tap Build
I need a custom tap
M20 Tap
M20 x 1.0 Thread tap

Timestamps
0:00 - Introduction
2:20 - Cutting Geometry
4:20 - Lathe Machining
7:11 - Milling The Shank And Flutes
10:52 - Heat Treatment
14:44 - Grinding Relief and Testing

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