StarReloaders.com Discussion Forum
Star Reloaders Discussion Forums => Star Reloaders => Topic started by: z4lunch on July 20, 2012, 10:52:58 am
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Anyone no what the thread pitch is on the powder tube, where it
Threads into the top of the charge bar housing
Thanks
Steve
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Greetings,
The thread size is 1/4-27 F-PTF.
You will not find a tap at the local hardware store. It is a special thread.
Cheers,
Dave
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Thanks Dave...
Email sent
Steve
Greetings,
The thread size is 1/4-27 F-PTF.
You will not find a tap at the local hardware store. It is a special thread.
Cheers,
Dave
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Dave
Who has those for sale....??
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Greetings All,
I sent an email to McMaster Carr for a tap. I have been unable to locate one on the Internet.
I have a 1/4-27 NPT tap I was going to shorten.
I decided to set up a piece of scrap in my lathe and tap it full length with my existing tap. Bad news, it does not cut large enough.
If McMaster does not come through, I will attempt to machine a tap myself. Or, at lease a possible thread forming tool. Enough to repair damaged parts and possibly thread new ones.
Cheers,
Dave
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Dave
Aren't we talking about a 'DIE' not a "Tap' ... ???
Die for the Powder Tube.. :D
Tap for the Powder Slide Housing Cover Plate.. :D
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Greetings,
I am working on a tap to repair a powder housing.
Cheers,
Dave
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Greetings,
This thread has been most challenging and educational.
Based on SAE Document J476A (1961), (link below) on page 15.22 is a section that deals with non standard threads, such as the powder hopper cover.
So, my latest calculation indicates the thread is a 9/16-27 Dryseal SPL-PTF, OD 0.563.
So far, I have machined and heat treated my "special tap". All that remains is to get it sharpened and test it out. I have screwed it into several powder slide tops and I think I have a keeper.
Another note. There is someone selling powder shutoff devices on eBay. While looking at the photos of his/her parts, the thread did not seem tapered. I wrote and asked...
"Is the threaded portion a tapered or straight thread? My existing powder
hopper has a tapered thread."
The answer I received was...
"The threads in the special fitting ,and the threads in the valve are 9/16 -
24...
streaght....it works with my press ,and have sold alot of valves
with no complants...."
I suspect that the part starts into the Powder Slide Cover; but, with continued use will damage the original threads. Buyer beware...
http://www.google.com/url?sa=t&rct=j&q=sae.j476a.1961.pdf&source=web&cd=1&ved=0CEMQFjAA&url=https%3A%2F%2Flaw.resource.org%2Fpub%2Fus%2Fcfr%2Fibr%2F005%2Fsae.j476a.1961.pdf&ei=qH4pULjyOePqiwLYr4GQCw&usg=AFQjCNHWOzTtImODBbPwqCiWMW1fQLptTA&cad=rja
Cheers,
Dave
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Greetings,
I finished my special tap for the #70 Powder Slide Housing Cover.
If you have a Housing Cover with a buggered thread, contact me via email and I will see what arrangements can be made to remedy the fault.
Cheers,
Dave
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Greetings,
The thread size is 1/4-27 F-PTF.
You will not find a tap at the local hardware store. It is a special thread.
Cheers,
Dave
I just checked the thread, on a Star powder magazine, that I have by my computer... My Starret pitch guage says that dave is spot on with his thread callout.
Bill
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Greetings,
The thread calculates out to a 9/16-27 Dryseal SPL-PTF, OD 0.563
Again, taps are not available at the local supply houses.
I also found that the #54 Steel Ball Plug is the same thread size.
Cheers,
Dave
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Dave,
If someone were to remove the ball plug and taking care not to cross thread the powder housings threads could the threads be chased using the ball plug female threads? A lot like running a buggered bolt onto a nut if you don't have the die.Just a thought.
Thanks.
Semper Fi
MikeA
Las Vegas, NV
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Greetings,
The thread calculates out to a 9/16-27 Dryseal SPL-PTF, OD 0.563
Again, taps are not available at the local supply houses.
I also found that the #54 Steel Ball Plug is the same thread size.
Cheers,
Dave
Dave, is it tapered also?
I just happened to have one of the Steel Ball Plugs beside me here...
The ball plug does not want to thread into the powder slide, where the Powder magazine goes. It goes about two turns and then starts binding, While the powder magazine easily threads into and goes to the bottom of the threaded area.
Bill
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Greetings,
I took the tap I made and was able to thread it into the hole for the ball detent. Without access to the original drawings, reverse engineering is all I have. I did not try the ball detent plug in the powder housing. Perhaps I will out of curiosity.
I calculated the density of the powder slide housing and it "appears" to be a Zinc alloy, similar to Zamak-3.
You might get lucky trying to clean up the threads of the powder slide top with the ball detent plug; but, you could end up with two damaged parts. If your powder housing top is damaged contact me about repair.
If you have access to a good Machinist, give him/her the thread specification and have a male thread machined. You might be able to iron out the damaged thread with the steel part.
Cheers,
Dave
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Greetings All,
While machining some Powder Hoppers, I decided to post an image of what is involved in cutting the 9/16-27 Dryseal SPL-PTF, OD 0.563 thread
http://home.comcast.net/~fc60net/TaperThread.JPG
In the photo, you can see the part is shifted off axis, by moving the tail stock away from center, to the correct angle for the thread. (3/4" per foot, the standard pipe thread taper.)
At the very right is the brass nose piece that is inserted and clamped in the aluminum arbor.
The indicator is to control the threading operation so that I do not nick the main body of the part as the cutting tool feeds to the left.
"Maschinenvergnügen" (The joy of machining)
Cheers,
Dave
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Nice!! Thanks for sharing
steve
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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
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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
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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
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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
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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