French influence on U.S. Armories

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FredC
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Re: French influence on U.S. Armories

Post by FredC »

It really is a puzzle why these odd thread pitches were chosen. I am not sure what thread pitch the original Maudslay screw cutting lathes used on their leadscrews. But a small pile of gears allowed them to cut many different TPIs. Already mentioned was 26 and Mausers used 22 on their trigger guards. Both these have 2 prime numbers as factors (2 and 11, 2 and 13). I have a sneaky suspicion that armory gunsmiths that gunsmiths were making it hard for just anyone to duplicate the parts that they used to have spend days making. On modern lathes with Imperial leadscrews I have only seen 8 and 4 pitches. Any thread divisible by 8 can be run on an 8 pitch leadscrew without use of a thread dial, gearing is fast an easy. If 24 or 32 TPI had been chosen for Krag and other screws it would have been so much easier to make the screws, taps and dies by the armories. Numbers like 22, 26, and 30 may have required custom made gears?
I leased the machines of a man whose father built trenching machines. They chose bearings and other parts that were not readily bought off the shelf to make customers come back to them for spare parts. Not sure if some perverse reasoning was involved in the choices of these odd thread pitches. Maybe it made it harder for an enemy to maintain weapons found on a battlefield?

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butlersrangers
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Re: French influence on U.S. Armories

Post by butlersrangers »

I think we have to look backwards to find the origins (of U.S. gun threads).

I suspect the motivation, (with the advent of machinery for mass production), was not to make the 'best' screw threads, but, to make 'existing' and at least adequate screw threads, uniform and faster.

This is all opinion and conjecture, from out of my head, and I might be totally wrong.

It would be fun to have some early U.S. Arsenal made muskets, rifles, and Hall breech-loaders to study & collect data from and compare with the French arms, that we copied.

(An unrelated aside: When studied, the 'Sign Language' of the American Deaf population had nothing in common with the Sign Language of Great Britain. It was found, however, to have many features in common with the Sign Language of the Deaf population of Paris.
Why? Because the first American School for the Deaf, Gallaudet in Washington D.C., had French Teachers).

FredC
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Re: French influence on U.S. Armories

Post by FredC »

Some of the earlier links I made cited attempts at maximizing the strength of threads. The Whitworth with the 55 degree flanks and rounded roots and crests were probably part of the movement. I guess they were going for maximum after the screw cutting lathe and mass production were on the horizon. the problem with the large crests and roots besides size control and fitting was the reduced flank area that actually carried the load. Geometry of the 60 degree thread with a small flat on the crests and roots was just so much easier to make and very strong to boot. With the US Unified system (1920s I think) and a standard course and a standard fine thread gave users a choice. Technically a course thread has the stronger tapped hole as the Vees cut pretty deep into the fastener. The fine thread will have more cross sectional in the fastened but a little weaker in the tapped hole. That weakness can be made up for with a longer area of engagement or a stronger material.

It has been a long time since I owned a Swedish Mauser maybe someone could check the thread form on the trigger guard screws, are they conventional looking and 22TPI?

Unwillingness to change an outdated fastener probably led the US to not change the screws in the 1903 till the end of production in 1945 or whenever the last one was made. (Maybe the Garand has Unified threads?) The Germans did not change the 22 thread (with a Unified appearance) per inch even till recently as I made screws for new commercial Mausers as late as 1995 when they should have been metric.

Yeah, on sign language they missed the boat on having a universal language.

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butlersrangers
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Re: French influence on U.S. Armories

Post by butlersrangers »

Language is tricky ... problem goes back to Babel, I think.

(I just used American Sign Language as an example of something with kind of unexpected roots).

Plan a language? "Esperanto" didn't work out so great for the Austro-Hungarian Empire. :lol:

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butlersrangers
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Re: French influence on U.S. Armories

Post by butlersrangers »

Fred: I pulled the two guard-screws on a model 1894 Swedish carbine, (made in 1914 at Carl Gustafs Stads).

As you predicted, the screw-threads were 22 t.p.i. (The threads are pretty 'V' shaped).

Judging by finish, the two screws are or different vintage. The newer looking screw has a thread diameter of .247". The older looking front-screw has a thread diameter of .250".

Since some of the early Swedish rifles and carbines were made on contract by Oberndorf - Mauser and the Swedish Mauser is basically derived from the Model 1893 MAUSER, it is not surprising screws and many parts interchange.

FredC
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Re: French influence on U.S. Armories

Post by FredC »

Looks like the Germans were an early adopter of the modern Unified style thread form. For all I know them may have invented the thread style. I am not sure if it is even possible to create an accurate time line on screw development. Swiss developed the Swiss machines that feed a bar through a stationary bushing, a real advance for long parts without large diameters. Seems like all the other high production machines were developed here and exported around the world. Brown, then Brown and Share, Davenport, New Britain-Gridley, Acme-Gridley, Cone-amatic. Later foreign machines would have been Index, Guildemeister (German) the English had a multispindle automatic but I forgot the name, but I think it was based on the Gridley principles as well as the Guildemeister. My old boss that had the 3 New Britains is still in business one of the machines was pre war, the middle one had a WW2 war production board stamp on it and one later machine. Each has made untold millions of parts. Mr. Gridley was pretty smart.

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butlersrangers
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Re: French influence on U.S. Armories

Post by butlersrangers »

'FredC' - I was just wondering, why you wanted the Swedish Mauser guard-screws confirmed?

IMHO - It would be interesting to examine Danish and Norwegian Krag screws and document their threads and dimensions on the KCA Forum.
I doubt there is any relationship to U.S. Krag threads, but, it would be neat data to know and compare.

(I don't personally have Danish or Norwegian Krag examples to measure).

FredC
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Re: French influence on U.S. Armories

Post by FredC »

The puzzle why Mauser used imperial trigger guard sizes later in 1995, probably meant the very first Mausers used the same threads. You sort of confirmed that. Amazing continuity from the first ones to very recent ones. We are back to thread forensics to trace who copied who and who influenced who. Wonder if Paul Mauser originated the thread form or was he influenced by an American commercial screw he saw on a machine tool?

How bout a Garand owner measuring what is used there. Gotta a feeling they will be unified thread forms and pitches.
European Krags were they influenced by Whitworth or the new metric screw forms?

Anyone know when the last 1903 Springfield was built? To maintain screw interchangeability it was probably the same as the original US Krag. Brownels did not list any exceptions when it showed the same screw for both.
Last edited by FredC on Tue May 11, 2021 1:40 pm, edited 1 time in total.

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butlersrangers
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Re: French influence on U.S. Armories

Post by butlersrangers »

There are not a lot of screws on an M-1 Garand. Sort of six "screws", I believe.

IIRC - #1 & 2 - Middle-swivel and stacking-swivel screws, likely have the same thread as Krag and 1903 & 1903A3 swivel screws.

#3 - The butt-plate top screw is a wood-screw.
#4 - The bottom of the plate is secured by a very 'long-shank' machine-screw, that threads through a hole on the tang of the butt-swivel. (The one piece butt-swivel inserts into an oval hole near the toe of the stock).

#5 - The gas-cylinder 'plug' is threaded and kind of a screw.
#6 - The complicated rear-sight pinion and knob assembly has a visible screw head.

Oh ya, the barrel-shank is threaded and screws into the receiver, too.

They probably stopped making the Model 1903A3 in 1944. The butt-plate and butt-swivel wood screws, the trigger-guard screws, and sling-swivel screws, will work on a model 1903 Springfield and a Krag. (The 'parkerized' finish will be wrong).

The front barrel-band screw for the 1903A3 is unique and will not work with the 1903 and Krag.
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Parashooter
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Re: French influence on U.S. Armories

Post by Parashooter »

butlersrangers wrote: Tue May 11, 2021 5:10 amThere are not a lot of screws on an M-1 Garand. Sort of six "screws", I believe.
Did you overlook the front sight screw? :o

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