Breechblock pin

[sandromxp]

So I was taking apart my spare toggle and the breechblock pink came out in 2 pieces. It pushed out about half way and I just gave it a light tap and it came out in two pieces. The reason I got the spare complete toggle was so I don't damage my matching one. The original one I can't push out the breechblock pin and I didn't want to damage it. Now I worried about the pins. I'm thinking of replacing all the pins in the toggle that I'm going to shoot with. Also not sure which pins I should get. Repo or original used ones? I'm thinking of taking a ride out to Sarco to pick up some spares and Springs.

Sandro

[4 Scale]

If it were mine I would do a 100% detailed strip of the toggle to make sure no other surprises. I'd suggest contact LugerDoc (Tom Heller) for a replacement pin.

Once removed and inspected, if all other components are OK I cannot see why any would need to be replaced.

I replace or modify springs only when there is an issue indicating a need. The Luger is a balanced system and I would think spring replacement on a perfectly functioning pistol could possibly require further work to achieve proper operation.

[DonVoigt]

A broken pin is unusual; replace it and inspect the rest.
Then move on and don't worry.

[sheepherder]

Originally Posted by DonVoigt

Then move on and don't worry.

..."Be happy???"...

Is that the ~3/16" dia pin about 5/8" long??? That is unusual...I'd inspect that breechblock very carefully...

[mrerick]

You may find that a replacement pin will break pretty quickly after you replace it.

I've had this happen in one of my Lugers. The problem is that there is excessive play along the length of the toggle train caused by wear. In the case of my Luger, the breech block pin area had excessive wear in the breech block and front toggle link holes. This slight looseness is enough to cause the pin to snap when the gun is fired. This may relate to headspace since the cartridge head ends up well off the breech face during firing. We're talking a few thousandths of an inch.

The solution is to use an oversize pin and to correctly resize the holes in the breech block and front toggle to fit the oversize pin. This eliminates the play between the breech block and forward toggle.

The breech block is hardened, so enlarging this hole is not trivial.

[Lugerdoc]

I have plenty of standard diameter forward (breech block) toggle axels available $5 each and a few that are slightly oversized @$10 + $5 S&H. TH

[Rick W.]

I personally think there is some merit in the posting above about toggle linkage slack due to wear or previous harder than normal use(abbynornal hot loads, long headspace, misfitted/worn parts).

We all know what inappropriate headspace/gapspace can do for the brass cartridge itself, extractor, and/or the firing pin capture in the breechblock.

I too have a Luger toggle that features a replaced pin between the breechblock and the middle link. You can tell it is way oversized. Not sure how it was done by those unknown to me, but strongly suspect that a special jig and carbide reamer were used to fit the new pin into the newly reamed holes in the two parts.

One would think that slack in a train would increase the forces on said interconnections, kinda like getting a run at it versus a start up push; kinda a crude rendition but helps me try to come to grips with such.

On occasion I have had a rifle barrel that would not budge with my 250lbs at 3 feet, and my feet off the ground and me moving. A sharp blow with a hammer on the wrench pulled it off in one blow. Kinda like the air impacts you see wheels being mounted. So one could imagine an analogy to the blow being applied to the toggle train with loose fittings between the links.

Seems like, my opinion only, that the fix of just replacing a pin in an oversized or ovalized hole will not last long. I know people do it all the time, but guess I would not choose not to do that. One could imagine the reaming routine being kinda like tightening up double shotguns, both parts are reamed in place to a precisely fitted pin.

Just pure opinion from a casual reserver. I am sure the real experts have their own opinions and rightfully so.

[DonVoigt]

Depends on if one intends to shoot the pistol a little or a lot, a lot being relative of course.

I cannot imagine firing a luger that has exhibited a problem like this "a lot" after it has been repaired.

So as usual, it depends on what one is trying to accomplish. If one wants a pistol to shoot for 1000's of rounds, buy a near new late issue Mauser; or replace the toggle train on this one for shooting.

It is entirely possible the pin broke because it was flawed when made, or too brittle.

[sandromxp]

I took a closer look at the pin and i saw the crack going thru what looks like a circular imperfection on the pin also saw a few places that looked like the pin had a flat spot but was almost oval i have two photos that you can see the damage

probably a defect in the pin? I'm going to get some pins from Lugerdoc and have the gun looked at

I wanted to change the toggle so i didn't damage the matching numbers on my 1940 Mauser 42 and now I'm glad i was taking apart the spare toggle

Sandro

[Diver6106]

Note that straight pins can be made from a drill bit of proper size. These are very strong, and if used for testing, can indicate other problems if they break. It also avoids breaking another expensive vintage pin.

[mrerick]

One way to check is to try a replacement pin in the forward toggle and breech block holes to see if there is any play. If there is play, then wear is contributing to the problem. I had multiple standard size pins snap in a luger that eventually required an oversized pin.

If it seems to fit properly, try shooting it. If there are still problems, the pin will snap apart again.

When Mauser re-engineered things in the 1970's, they reshaped the ends of the pins (concave rather than flat ends). I believe that this was to improve distribution of the forces acting on the pins during the firing cycle.

[DonVoigt]

From the looks of that pin, it was worn out; and likely placed into your replacement toggle which I would bet is mismatched or worn also. It may not even be an original pin, but one made from a drill bit or rod; if an "inch" dimensioned piece were used, it may also have been undersized as the original is nominally 5mm. 3/16" is close, but about 9/1000" undersize to start.

The drawings show the hole in the breech block to be spec'd at 5.02 + 0.05mm.
The hole in the toggle at 5.05mm +0.1mm
The pin at 5.0 nominal is spec'd at 5.00mm -0.05mm

Hence designed with about 0.1mm "clearance" or about 4/1000 of an inch to the toggle, and about twice that to the breech block.

These short, "fat" pins are quite strong- they don't just "break".
The shape of the ends of the pins-flat or slightly concave - would be irrelevant.

You guys are way overthinking this, JMHO.

[mrerick]

The pins are hardened, are brittle and tend to snap / fracture. I had it happen a couple of times before replacing a pin with an oversized one.

[Rick W.]

Sounds like Mrerick has been thru some of this stuff. I generally like some slack in some things, but not really in a Luger toggle train. Slack has a lot of different contexts......

In the first picture of the broke pin, there seems to be an area of wear or setback(cannot feel from here) that the crack might have originated from. Just a guess on my part.

One would think that the areas would show up near the interfaces of the two parts, the rest of the pin proper is supported in a way, unless way worn or whatever reduced in dimension.

I suspect that John S.'s blueprints would give the dimensions of said pin and adjoining parts. That is where I would go for starting dimensions or the Dutch Luger book appendix. In my Luger, the enlarging of the respective holes is probably less than 10%, as pointed out earlier in another post, if the holes are a lot larger on one side etc, then perhaps replacement parts should be considered.

I would suspect that the steels have improved over the years, but still are machined up somewhat soft in a lot of cases then hardened with a furnace. Seems like there was some verbage on such in a posting here on this forum a while back, perhaps in a Navy sense, someone wanting to sell reproduction pins, but not sure the secret information on pin makup was given or not........... we have a search engine on this forum if so interested.

These parts a getting long in the tooth sorta speak, some around seem to be a bit used, sometimes not..........pays your money and takes your chances...........chance is hard to take in breeching criteria.

[DonVoigt]

Originally Posted by mrerick

The pins are hardened, are brittle and tend to snap / fracture. I had it happen a couple of times before replacing a pin with an oversized one.

Mark,
If they are brittle, then they are not hardened and drawn correctly.
There is a difference between "hard" and too hard(=brittle).

More likely what we are seeing is stress cracking emanating from a flaw or inclusion in the original material.

Rick,
I gave the drawing dimensions and tolerances in my post above.
The toggle train is designed with some "looseness", but not a lot.

Sandromxp,
If the pin was received "broken" in the replacement toggle, I'd send the whole thing back; and start over.

[sandromxp]

Thanks guys. I'm going to take the whole toggle apart and inspect the pins. I'm going to get a new pins from the Lugerdoc and have a gunsmith inspect it before I take it shooting. Does anyone know of a good Luger gunsmith in the Ft Lauderdale area?

Sandro

Now it looks like I'm going to pick up a shooter too! And that's how it starts!

[mrerick]

Sandro, send it to Tom in Missouri. He's the best. Very few local gunsmiths have ever worked on Luger actions.

Don, the gun arrived with a snapped forward axle pin, so I replaced it with a new (original) one. First shot snapped the new one. Installed another new pin. Snapped within a couple of shots.

I obtained an oversized pin and installed it after slightly expanding the forward toggle and breech block's axle holes to fit it. Shoots fine now without snapping pins.

The play prior to installing the new pin was well below 10 thousandths of an inch. The ammo was standard velocity FMJ.

[sandromxp]

mrerick Taking your advice. Sending the Luger and extra toggle to Lugerdoc and going to get it checked out and have the headspace checked. It looks like I'll probably going to get a shooter too! Looks like the 1911 is going to have to wait

Thanks all for the advice!

Sandro

[Eugen]

Originally Posted by sandromxp

mrerick Taking your advice. Sending the Luger and extra toggle to Lugerdoc and going to get it checked out and have the headspace checked. It looks like I'll probably going to get a shooter too! Looks like the 1911 is going to have to wait

Thanks all for the advice!

Sandro

Keep us posted after Mr. Heller fixes it and you take it to the range. We all want to hear the results.

[DonVoigt]

Thanks for the info Marc,
seems like lightning struck you 3 times on that pin.