On Jan 13, 1:01*pm, Randy333 wrote:
I need to do some thread milling, never did it before!! *I need to cut
2- 1-1/4"-11.5 NPS exteranl threads, a 1-3/4"-16 external and a
1-7/8"-18 internal thread.

I found a thread mill for 11.5 NPS but in the catalog it's listed as
internal only, why? *Any place I can get this at under $300 bucks that
MSC wants?

Remove 333 to reply.
Randy

I'm going to guess that it pertains to the smaller percentage of
thread when cutting internal. If that is correct, then using a thread
mill designed for internal cutting should produce a truncated root
when used to mill external threads.