Tap drill depths for taper reamed NPTF threads 1

[stfgrizz]

I have some standard minimum tap drill depths I use for up to 1 1/4 NPTF taper reamed internal threads. I'm looking for standard minimum tap drill depths for the larger sizes up to 3" and I can only find an old chart in my files for NPT threads and it is largly illegible.

Thanks in advance.

 

[fcsuper]

I don't have the book on me today, but have you looked in the Machinery's Handbook?

Matt
CAD Engineer/ECN Analyst
Silicon Valley, CA
sw.fcsuper.com
Co-moderator of Solidworks Yahoo! Group

 

[deanc]

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

http://www.osgtool.com/Technical.asp?tid=1

http://academic.evergreen.edu/projects/biophysics/technotes/fabric/js-tap.htm

 

[stfgrizz]

Nothing in Machinery's. I didn't find anything in the other links either. Thanks for the effort though.

 

[unclesyd]

See thread281-141727

There is some very good information here that should cover you requirements.

 

[stfgrizz]

Thanks -

Looks like I can get what I need from this stuff.

 

[unclesyd]

I was in a hurry when I post the information above. Here is a couple of additional comments.

The ME Threads program is very good and inexpensive. It would be a great asset if you deal in threaded fasteners very much.

I was taught, a long time age, that on pipe threads that you use the rule of 12's. Count up 12 threads, measure and drill to that depth.