NPT Tap Hole Depth 1

[Eltron]

Does anyone have a chart or a reference where I can look up the minimum hole depth needed for a blind NPT tapped hole? It seems like something that should be easy to find, but I haven't had any luck. I've already looked in the Machininst's Handbook, and I want to avoid the trial-and-error approach. Any suggestions would be appreciated.

 

[mrainey]

Look here.

http://www.eng-tips.com/viewthread.cfm?qid=138915&page=2

Manufacturing Freeware and Shareware

http://mrainey.freeservers.com

 

[Eltron]

Thanks for the reply, but that post really just deals with the effective thread length and only for 3/8 threads. I already have that information. I'm looking for the minimum blind hole depth needed to make those threads with a standard NPT tap.

 

[mrainey]

Actually I tried to answer that question in the referenced thread, everybody else got into effective thread length.

I have a free program that displays, along with many other things, a reference tap depth for all common NPT sizes (use the Threads module of the program). I've used those numbers many times in my work, and never had a problem with going too deep.

http://mrainey.freeservers.com/MEConsultant20.html

Manufacturing Freeware and Shareware

http://mrainey.freeservers.com

 

[Eltron]

That looks like a decent program, but only the first three hole sizes are available. It seems like there should be a chart or a simple calculation that is available out there somewhere. Any other suggestions would be appreciated.

 

[mrainey]

Eltron,

The program I referenced (ME Consultant 2.0) is free and contains data for all common NPT threads.

As stated in the other thread, my source was Guide to Threads, Threading, and Threaded Fasteners (Modern Machine Shop, 2004), page 262.

Sorry, I don't know of a free chart.



Manufacturing Freeware and Shareware

http://mrainey.freeservers.com

 

[Eltron]

Thanks, again. You've got a nice little program there. That is exactly what I was looking for.

 

[surfdog]

I did a google search a few months back and found data....it is out there........rough check the thread gage to where the flat is and that should give a good idea of how deep to go

 

[Chappy2]

Emuge offers an excellent chart for NPT min hole depths