Powder tube thread pitch

[z4lunch]

Nice!! Thanks for sharing
steve

[fc60]

Greetings,

Time to bring this topic back to life.

The thread on the Powder Hopper is TAPERED, not STRAIGHT.

Use caution when purchasing or making accessory powder hopper parts.

I have repaired two powder slide covers that had "buggered" threads from folks inadvertently using parts with the wrong thread.

Good news is that Bruce Williams has purchased the Star Company and may have replacement covers to offer in the future.

Cheers,

Dave

[Jerry Lehrer]

Dave,

There is a tool supply outfit in Brooklyn called Victor Machinery Exch. that supplied the correct tap and die for the powder supply system.

It MAY even be the outfit that supplied Star originally.  They have been in business for about 90 years !!  I have put Scott/Wes Lorenz
in contact with them.

Jerry Lehrer

[varmintpopper]

American Dryseal Pipe Threads (NPTF and NPSM)

American Dryseal Pipe Threads (NPTF and NPSM)

This commonly used connection incorporates two methods of sealing. The male NPTF (Dryseal) tapered thread will mate with the NPTF tapered female, which is usually a port, and seal when the special threads are crushed together. Male PTF (Short Dryseal) are identical to male NPTF threads except that the thread lengths have been shortened by one full thread from the small end of the taper. Additional sealing aids such as pipe dope and Teflon tape are often used with theses threads. If the male has a 30° seat it will mate with the 30° cone seat in the NPSM straight thread swivel female, usually found on adapters, and is mechanically held together by the threads. NPTF and NPSM are not interchangeable with the British pipe threads.

Click here for a guide on how to properly measure threads.

Click here for a printable, actual size pipe fitting profiles. You will need to have Adobe Reader to view and print the file.


American Dryseal Pipe Threads (NPTF and NPSM)
Dash
Size   Inch
Size   Thread   Male
Thread
O.D.
mm   Male
Thread
O.D.
inches   Female
Thread
I.D.
mm   Female
Thread
I.D.
inches
2   1/8   1/8 - 27   10.3   .41   9.4   .37
4   1/4   1/4 - 18   13.7   .54   12.4   .49
6   3/8   3/8 - 18   17.3   .68   15.7   .62
8   1/2   1/2 - 14   21.3   .84   19.3   .76
12   3/4   3/4 - 14   26.9   1.06   24.9   .98
16   1   1 – 11-1/2   33.3   1.31   31.5   1.24
20   1-1/4   1-1/4 – 11-1/2   42.2   1.66   40.1   1.58
24   1-1/2   1-1/2 – 11-1/2   48.3   1.90   46.2   1.82
32   2   2 – 11-1/2   60.4   2.38   57.9   2.29

[GeraldChainsaw]

fc60,  I have to confess,  I'm the one selling the powder shut off valve,  but if your going to quote me,  at least get the numbers right,  I said 9/16ths x 27tpi,  and straight  thread is right,    if it has a taper which it may have,  dosen't  seem to be a problem,  for me at least.   guess that's why I havn't sold any on ebay,   as far as stripping the threads,  no one was asked to see how strong they were, it is plastic.   jerry

[fc60]

Greetings Jerry,

I contacted Victory Machine Exchange as you suggested. No luck. They did offer to manufacture them. A copy of the emails are below in blue text. Victory does have a lot of weird taps along with McMaster-Carr.

I did machine a tap a while back that works okay in soft metal such as the Zamak (Zinc Alloy) Star used for the powder housings and lids.

I may have a go at machining a die for this odd sized thread in the future; however, too many other projects in the way....

We could only manufacture this from a print.

Marc Freidus

Victor Machinery Exchange
56 Bogart St
Brooklyn, NY 11206
www.victornet.com

Phone: 718-366-9293
Fax: 718-366-7026

From: David
Sent: Tuesday, April 14, 2015 6:21 PM
To: [no e-mail]@.com
Subject: Odd Size Tap and Die

 
Greetings,

I searched your excellently stocked website for a special tap with no luck. Perhaps I am looking in the wrong place?

I seek a 9/16-27 Dryseal SPL-PTF, OD 0.563 (It is a tapered thread, the same as an NPT taper).

If you also have die, that would also be a good find.

With kind regards,

David