Internal G76 1/2-14 NPT Thread

[aressler35]

I'm not sure how to start making an internal 1/2-14 NPT thread using a single point tool and using a 2 line G76 on a DMG Mori.

Question 1: What size hole to I put in the part using a turning tool? What is a large diameter and what is the small diameter? ( I know the angle of a pipe thread is 1.7899 deg.)

Question 2: What does the G76 lines of code look like and why?
Reference:
G76 P000000 R
G76 X, Z, P, Q, R, F

Any help will be appreciated.

Thank You

 

[Ox]

I don't know what program that I could cut/paste one of those from, but the code would look like any other thread, except that you would need to add an R+ value for the amount of taper in relation to your Z stroke. I think that R is in diameter and not rad, but not sure. Been quite a while since I have done those.


--------------------

Think Snow Eh!
Ox

 

[yardbird]

You might have a look at this thread. It's going to be the same only you'll be cutting an ID pipe thread. The R is a radius value. And like Ox mentioned it's the X distance of total Z move.

Don't get shook up if it doesn't come out perfectly on the first go, just fudge it around until whatever your checking it with looks good, then leter rip. Save this program somewhere titled "single point half-inch-14 ID NPT" so you only have to do this once.

Good luck....

Brent

http://www.practicalmachinist.com/vb/general/o-d-npt-thread-344739/#post3102810

 

[sinha]

R = L/32
where L is the total axial travel.