OT- #8-24 threads?

[cooncatbob]

I have a client who wants me to make him a custom handle for a 100 year old GEM single edge razor.
The Gems I've dealt with in the past have had either #6-32, #8-32 or #10-32 male threads with the older razor being the smaller and the newer razors using the larger.
I usualled tap the end of the handle then locktite in a piece of threaded rot with 1/8th inch sticking out to screw into the razor head.
The client is in Croatia and couldn't determine the thread size so he sent me his old handle.
The major diameter of the threads are .160 and my thread pitch gauge shows 24 TPI so this would make it a #8-24.
I can't find a listing for a thread this size.
I'm I screwed?
I don't know it I'm up to cutting such a small thread on the end of a spindle.
The best solution I can think of is to have the client send me his razor head, I could retap it for #10-32 threads and I could also redo his old handle for #10-32 threads.

 

[bigmac]

Dunno, Bob. There are some odd threads used by gunsmiths, but, not being one, I don't know what they are. This could also be British or some other odd thread that is used in Europe. You may have already thought of the best solution. I assume that you've already checked metric possibilities. Sorry, not much help. Ed

 

[tjwal]

You can cut the threads fairly easily if you turn the spindle over by hand. A crank on the outboard end is a big help but I've done it by turning the large pulley on my back mounted countershaft.

It would be easire to fit if you had the head to to use as a gage.



JohnW

 

[jimwallis]

I'm sure I've seen reference to this thread before (did I work out my 13" way wiper screws were this size?) but it is non standard and looking round my list of UK suppliers of taps and dies I don't see anyone offering taps or dies in this size.

I could be getting mixed up with 10-32 and 10-24 though, we only seem to get 10-24 over here.

It doesn't match any regular coarse metric thread as far as I can tell.

Er, I've not been much help either.

 

[Paula]

Travers Tool lists 8-24 taps and dies in its catalog (under "special thread" category). No doubt other similarly-sized houses would carry them (MSC, etc.)

Paula

 

[promacjoe]

Try British Standard Whitworth.
the Effective Diameter of a 3⁄16 24 is 0.1608.

But you still need the razor head to use as a gauge.


I hope this helps.

promacjoe

 

[The real Leigh]

McMaster-Carr www.mcmaster.com has #8-24 taps, but not dies.

You could cut external threads easily on any lathe that will do 24 tpi.

Don't know why this question is in the SB section rather than General New.

- Leigh

 

[James Rogers]

Try a hobby shop that sells remote control model airplanes and cars.

 

[whitis]

Looking at my 1920 edition of American Machinist's Handbook, #8-24 wasn't a standard size even then (when there were more standard sizes). American Screw Company had #8-32, #8-30, and #8-36 and the 1907 ASME standard defined #8-36 and also #8-30 and #8-32 as "special sizes". #10-24 was an ASME special size and elsewhere 3/16-24 was also defined in the "Milled Screw Mfr.'s Standard". These two are around 25mils larger - if you have flats on the outer surface, it could be one of those with the outer diameter turned undersized or stripped. Or if the threads are rounded, a rounded thread profile such that the major diameter is virtual. Or just less than 100% of full thread., which wouldn't have been that unusual.


There was also a 3/16-24 stove bolt size but 3/16 was the pitch diameter, not the major diameter. A Reed & Prince screw blank for a U.S.S. 3/16-24 rolled screws had an OD of 0.1566/0.1586. The OD would be bigger after rolling.

Given that #8-24 apparently wasn't a standard size, the thread might differ in other ways so I would check the thread dimensions and profile. It is easy enough to duplicate what you have but if you try to do it "by the numbers" you may find out the hard way that they didn't. You can grind a HSS bit to match the profile you have and hand crank while threading to avoid crashing into the shoulder. Sounds like it is only about 3 turns of thread anyway.