Thread: Interesting piece of maching work

I picked this link up on usenet tonight .
This is a pictorial on making a large tap ,I guess for tapping threads in drill pipe for oil drilling rigs or similar ,
The tap has two threads machined on it a 12 1/4" diameter thread and an 11 " thread .
Interestingly enough is the thread is cut after the tool is heat treated. I'm thinking the fine threads would get damaged during the high heat of the hardening process so they grind the thread in after wards.

http://www.widell.com/bigtap01.html

Kev.

I saw that some time ago. There was a link to it on, I think, the Practical Machinist forum. I seem to remember there was a fair bit of discussion about it and I also seem to remember someone who was involved in the manufacture of it saying something about it ended up not being used for some reason. (With my memory I could be wrong on all of the above LOL). It certainly is some nice work though,

bollie7