NPT Pipe Tap Feeds and Speeds

[Matthewkral]

Hey Guys,

I'm a relatively new programmer/machinist for a small shop. I've hand tapped NPT tapered threads before but have been tasked with programming them for the first time. I assume I'm overthinking it but just wanted to double check. I know to find out my feedrate for a standard thread (lets use 1/4-20) I would use 1 divided by 20, multiplied by my spindle speed to get my feedrate. The same should work for NPT tapered threads correct? For a 1/4-18 NPT Pipe Tap, I would just insert the 18 into my formula?

Just wasn't sure since the threads are tapered if there was anything I'm missing. I wouldn't think so but doesn't hurt to ask. Apologies for the noob question.

Any other tips or tricks for pipe tapping you think I could use would be cool too. Thanks!

 

[camhead420]

You are correct!

 

[Finegrain]

Assuming mill, not lathe ...

Ugh, ditch the NPT tap and threadmill!! You have a CNC mill after all. Threadmill gives you fine control over thread size, and no termination ridge that you get with an NPT tap.

Regards.

Mike