Metric Acme Tap

[terry_g]

I found a picture I took of a 12mm x 2.5 tap I made.
I needed to make a new cross feed nut for my metric SouthBend lathe.
Its made from W1 drill rod and hardened and tempered. It took a lot force to
cut the threads, you can see the twist it developed.

 

[DavidR8]

Wow, rather amazing (and lucky) that it twisted and didn’t break.