What are Pipe Minor and Major Diameters in Tapered Whitworth Threads?

[optics.tech]

Hello everyone,

Can anyone please tell me what is meant by the following terms:

Pipe Minor Diameter, Pipe Major Diameter, and Tapping Drill Size

in the following link?

http://www.gewinde-normen.de/en/tapered-whitworth-pipe-thread.html

Regards

Huygen

 

[timmay]

http://www.accuratescrew.com/TechTips/images/tip8_screw1a.gif should help. Also, the tapping drill size is the size drill used to produce a hole which can be tapped for a female connection.

 

[FredGarvin]

Tapered Whitworth threads? Hoo. That's something you don't see every day in my parts. I can only guess as to what is referenced, but it appears that, at some gauge point determined in the thread spec, the major and minor diameters are still of the pipe thread. The tap drill size is just that, it is the drill bit size you predrill the hole for to prepare for running the desired tap through.

One of our Brit friends will have to verify that. I can't find anything specific to this thread form in Machinery's under this title. It is probably referenced under a different description and I just haven't found it yet. I'll keep looking.

EDIT: I found it in Machinery's. The Major diameter is definitely the major diameter of the thread form. The pipe minor diameter has me a bit stumped. It is not the minor of the thread form. For example, for the 1/16 nominal size (the first in the list) the minor diameter of the thread form is listed as 6.561. In that table it is listed as 3. That must mean that the pipe ID is 3mm. Unfortunately Machinery's doesn't go into a lot of detail for the tapered thread form as it does for the straight thread form. I will still have to yield to one of our European members for some assistance on this one. Good Luck.