sten gun

[Brit plumber]

If that were the case, why does the EMER for repairing loose bushings call for welding?

Desperation?

Seriously though, I have no idea. There's bound to be a good reason for all this and It's not something I've thought to much about.

Perhaps hangover from the Mk1 where you couldn't weld it?

[Vincent]

The Mk3 gun bushings were also riveted and soft soldered. It makes it fairly easy to get the bushings out if you need to. That’s the only reason I can think of for using soft solder.

One of my Lanchester magazines came apart recently. It wasn’t the usual failure where the retaining plate flies off into the grass never to be seen again… followed by the spring and platform. This time the reinforcing sheath stayed in the magazine housing and only the body came out. It turns out the reinforcing sheath was only held on with soft solder and not spot welded like others are.

[Flying10uk]

For someone like myself who works in the metalworking industry the question of how the bushing was attached during manufacture when it was not done in the manner that I would have expected is very interesting. I have not been criticising the way in which the bush was originally attached but rather trying to get an understanding of why this method was chosen. I still don't understand why soft solder was used unless it was as Vincent suggests as an easy method to remove/replace.

[Vincent]

Soft solder and rivets is quick and easy. No skills required. I think it would be strong enough to last the predicted combat life of 70 hours.

They might have had issues with welding to the thin casing tube. When you look at pictures of early guns the trigger mechanism housing ears are welded with two spot welds on each ear. Presumably that was done to avoid warping the tube. Later you see a “cold weld” running the length of each ear. It’s a weld that doesn’t penetrate deeply. Most of it sits above the surface and as the name implies, it’s not very hot. On the Mk5 they spot welded the ears to the casing, further reducing the chance of warping the tube or having burn through.

The Mk5 bushings were riveted and brazed in.

[Peter Laidler]

Soft solder and rivets might have been a crap way of doing it, but the gun had a life expectancy of 70 man hours. After that it was beyond economic repair to repair it. That the last Stens in the UK Military lasted until 1972 must be testament to the crap method of manufacture and the sheer mechanical genius of Harold Turpin

[Flying10uk]

Peter, the EMER which Vincent has previously mentioned on this thread called for the bush to be welded in cases where the bush had become loose. Do you know when this EMER came out, please, and by 1972 did most of the Stens still in service have the bushes welded? Were rivets and soft solder used for the reasons suggested by Vincent or was there another reason for using this method, perhaps to give the joint some flexibility?

As previously mentioned I am not criticising how the joint was made but I am very interested in why it was decided to use this method.

I remember my metalwork teacher at school once told me that, under certain circumstances/conditions, a brazed joint can be stronger than a welded joint. I can't remember his reasoning behind this assertion but that is what he said.

[tankhunter]

Welding would only be used on a repair, where applicable.

If all other guns were Servicable, & did not have a loose barrel bushing. It would have been a waste of time & manpower to recall all the Stens in service. To do any work, that did not actually need it at the time. As they were Obsolecent as the Sterling was going/ was introduced. Thus obviating the need to recall the whole 'Fleet' in Service during that time period.

yes indeed, 70 Man Hours was the 'Guesstimated' life expectancy of a Sten in wartime. BUT.......Like the jeep, it served on in a HUGE number of cases. Without the need for major repairs or overhauls. For quite some time!.........Nothing lasts forever of course, & Inspections on a quarterly or six month basis at most units. By The Unit Armourer/s Ensured that any repairs or defects. Were effected by Him/them there. Or if needing the next line of workshop repairs. With jigs or equipment, not held at first line. They would have had this welding or other Repairs & overhauls, done there. (Field Workshops)

[Peter Laidler]

One other point worth remembering with this solder and then rivet method was that in REAL life, with an Advanced Primer Ignition (API) ignition cycle - as in the Sten et al, the face of the breech block will never (?) actually strike the rear face of that bushing (or the barrel of course) because the percussion cap commences detonation at .040" or less and certainly WILL have detonated the cap by .014" (or is it .017"?) before the breech block is fully forwards, in battery, against the bushing.

This means that you'll never get the shock loading of impact of the breech block on the bush because at .014" away, the now fired case is acting like a piston and starting to travel rearwards (at 60:1 against the bullet) effectively cushioning any metal to metal contact.

Clever man that Harold Turpin

[Vincent]

Good point about API Peter.

With my Mk5 Sten, the face of the breech block strikes the bushing after the last round in the magazine has been fired and the trigger is still being squeezed. The Mk4&5 Sterlings do the same. I assume that’s normal?

[Peter Laidler]

That is normal for all of them without a mag HOD. It really doesn't matter at all with the Lanchester and Sterling because the barrel is screwed in with a large diameter thread that ain't going anywhere (lanchester) and with a large nosecap in the Sterling. But, Sterling nosecaps did come loose and were a bit of a pig to fix because they were copper brazed, rivetted with drive rivets and rolled.

The loose Sterling nose cap was a Base Workshop repair for the Sterling. The gun was rotated on a spit and the muzzle was heated to the melting point of the braze. In the HOPE that the braze would melt and run into itself and in effect re-braze the nose cap to the tube. The foresight protector had to be wired on tight too otherwise that'd fall off! Mind you, if oil etc etc had got between the tube and the nose cap you were really wasting your time and the gun was ZF