Measuring internal Threads

Not sure if the 1 in 10 twist of the Enfield barrel will work. If anything it will be a tad on the fast side so I anticipate it should work OK on a slow mover like this. Kind of like windmilling a soft ball, only slower and not as flat a trajectory.
 
Here is TSJC compilation of barrel shanks. Yours might be in this document.
 

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Bamban, that is a cool resource. Lots of stuff. I see that the angle of the V is not usually included. I have similar chart out of American Rifleman in the 60's but it is not as complete as this one. Thanks for sharing. Unfortunately the Pieper is not in it. It was not a very common or particularly high end rifle. Probably not worth much effort but I would like to see it live to shoot another day. I'm a sucker for old stuff and keeping them going.
 
I'd use cerrosafe, but you don't have to pour the whole length. Plug up the bottom with play dough so you only have about 1/2" to pour. Coat the threads with Vaseline. While you are pouring, stick a screw driver in the middle so you have a way to unscrew it.
 
Earlier on when I said I was just throwing it out there. Sometimes I think just a different train of thought or like walking away for five and such so here is another I ll throw out there.
Could you not bore the hole and thread to what you can see from the outside? Or is there just not enough meat there and you d compromise the action?
Can I ask not knowing much about Gunsmithing? Is the reason there is use of such fine threads due to the fact that sometimes close enough has to work like someone stated ealier where threads were crushed together with the use of stuff maybe from another century that hobbyist would be interested to use to modify? Or am I out in left field?
 
Check Tom Lipton's video. He uses a material called woods metal to make a positive casting of a steering wheel spline. This might works for you. You should be able to unscrew the casting once its cooled and then take your measurements.
About 2minutes in to the video
Wood metal https://www.belmontmetals.com/product/woods-metal/
 
Since this was a Belgian made turn of the previous century firearm the thread is unknown. It seems to use various threads. Again, since the bore is so small it is hard to get a read on the thread pitch and profile. One cannot see the thread pitch gauge perpendicular to the gauge. I have played around with it a bit and think I have the thread figured out but still have some niggling doubts.


If their an unknown thread on an antique I would do some research, https://en.wikipedia.org/wiki/Belgian_units_of_measurement , their it says they were metric since 1820 ish.

So it's probably metric. if you can get a thread pitch gauge in their that should be ok to figure out by feal. You could then try making test threads and screwing them in.

Stu
 
Hey. Mark.
Some threads on barrels are quite fine V threads and some are quite coarse square threads. and everything in between. Check out the list that Bamban posted. I think the 1905 Ross has a double start 8 per inch square thread. What their reasons were is anybody's guess.

Stu, it seems that what was official measurements went out the window when it came to guns. As noted previously the German Mauser 98s used a British Whitworth thread. I think I'll try Cerro Safe and see for sure. A small plug of it as Derf and Aliva said with a screwdriver or something placed in it for removal seems like a pious idea. I'll check the video as well.

Thanks you all for your suggestions on such an arcane subject.
 
Well I poured some Cerro Safe but it don't turn our very good. I guess the receiver was not warm enough in spite of heating it before the pour. I'll try it again tomorrow with a heat gun trained on it.

It looks like the thread is 18TPI Whitworth but its hard to tell the difference between 55 and 60 degrees on such small threads tucked inside a small hole. Maybe tomorrow's pour will work.
 
OK. Got a plug made and measured. Having it out helps immensely. I have determined that it must be a British Standard Parallel Pipe Thread
19 TPI. How weird is that?
 
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