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-   -   Is this repairable ? (https://forum.lugerforum.com/showthread.php?t=30232)

alvin 03-29-2013 06:48 PM

Is this repairable ?
 
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Got a broken safety level. The hammer locking lug on it is broken. Cannot simply throw it away and put another one on, because it's numbered to the gun.

Is this broken lug repairable? A good level at bottom offers a reference shape.

alvin 03-30-2013 02:55 AM

Yes. It's for Mauser C96. This type of safety appears on early Mausers, and disappeared when large ring hammer was replace by small ring hammer. It's a pretty but fragile structure.

Safety level -- misspelled, it should be safety lever.

Vlim 03-30-2013 09:38 AM

During our last visit in Oberndorf, Mr. Repa, former Mauser and Walther gun smith, mentioned a new laser welding technique that could be used to weld material on a square millimeter level. The welding being so secure that it was even possible to weld parts without affecting the hardness of the surrounding area.

alvin 03-30-2013 11:57 AM

Thanks for the hints.

Now I have a plan. Find one guy to micro-weld a small piece of triangle-like steel on the lever, probably slightly larger than required. Then find another guy to micro-mill the steel into the "L" shape and size. There are a few service companies in local area doing "laser welding", not sure they would do this or not. None of them do gun repairing, but they don't have to know how it works on a gun.

cdmech 03-30-2013 12:43 PM

Why does the broken area look like a casting? How did the part fail?
Marc

alvin 03-30-2013 02:24 PM

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Quote:

Originally Posted by postino (Post 231641)
Why not build up the existing/broken area with weld??? Just trying to eliminate the square corner machining???

It's too big. The square corner cannot be skipped. It must be there. Otherwise, the safety lever cannot be pushed down (safety on) when the hammer is at the down position. That corner on locking lug leaves space for the hammer.

The top thin layer of steel is not optional either, it covers the underneath empty space to prevent sand or dirt to fall in.

alvin 03-30-2013 02:33 PM

Quote:

Originally Posted by cdmech (Post 231645)
Why does the broken area look like a casting? How did the part fail?
Marc

I believe the locking lug was hardened, so it's also brittle. Same is true for bolt head and sear arm. Especially sear arm, it may crack like a piece of glass.

It arrives me in broken mode.

alvin 03-30-2013 07:29 PM

Thought about another possible way, and would like to hear your opinion:

If cut the L-shaped lug off from a scrap lever, then silver braze it to the lever to be repaired, that will be simpler.

I can find a jeweler doing this. They handle tiny objects everyday. The question: will the joint be strong enough? Any thought?

alvin 03-30-2013 08:08 PM

This safety lever is not pushed up and down all the time. I think early lever design was dropped quickly by Mauser because (1) it's hard to operate; (2) the safety knob on/off position is not visually obvious; and (3) it's probably too fragile. But it's still needed in certain scenarios, e.g. unloading via removing magazine floor plate, safety better be on because these is a chambered round.

So, it's not really related with shooting very much. Even with this lever totally removed, the gun still shoots :)

Vlim 03-30-2013 08:18 PM

The safety was not only impractical. It was downright dangerous and Mauser C96 pistols were plagued by malfunctioning safety levers with lethal results.

cdmech 03-30-2013 08:40 PM

Whether or not a repair is strong enough depends on why it broke the first time. High stress during normal use or abuse, perhaps a dropped gun. Maybe it's just the picture, but the break looks to much like cast metal for me to think the part was strong to begin with. However, looks like an excellent surface for brazing.

alvin 03-31-2013 11:28 AM

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Just watched a few laser welding service provider's web sites. What they can do is amazing!!! Will still put this option into the highest preference, as long as they are willing to do it.

A sample picture:

Vlim 03-31-2013 01:51 PM

I think that laser welding should produce the best result.

An alternative is to build up enough welding material using TIG or MIG welding, followed by reshaping the part using small files and a lot of patience.

I fixed the tip of a C96 bolt a couple of years ago this way. The weld blended in perfectly. I used the base of a brass cartridge as protection and filler material to allow the welding material to flow past the bolt face. Since the pistol is retired and I merely wanted to preserve the original bolt, that was good enough for me. I built up the material so that I had enough area to file down again, followed by a partial polishing of the area. The weld blended in nicely with no obvious discoloration in the material.

alvin 03-31-2013 07:38 PM

Quote:

Originally Posted by postino (Post 231659)
You know however you repair it, it will still need 'fitting'...

Since I don't have blueprint of this part, I need to find a lever working on this particular pistol, so they can use it as a reference.

The first trial was a working lever from another pistol, the rotating stud on the lever could not even insert into the corresponding hole on the lock frame.

Then, tried another one, it's installed OK this time. When I push down that safety lever, my heart was bumping: I don't want to break another one. "Please, do not break" :) It worked perfectly, in two hammer positions. So, this good lever can be used as a reference.

Now, I see why this lever was numbered to the gun. Fortunately, the rotating stud was good on that broken lever.

alvin 04-01-2013 03:20 PM

They accepted it. Promised (1) the finish on the other side won't be ruined (because the heat input is so low); (2) the s/n on the lever will be kept, even the tiny "m" inspector mark sitting next to the broken lug will be kept; (3) it will be in the same shape and it will have enough strength.

Will report final result after it's done. This is hi-tech.

rhuff 04-01-2013 04:26 PM

That is fantastic news, and you can keep your pistol correct and be functional again.

alvin 04-01-2013 05:41 PM

Quote:

Originally Posted by rhuff (Post 231735)
That is fantastic news, and you can keep your pistol correct and be functional again.

Surely happy today. It's not all settled down yet, until it's done. I hope I will be satisfied.

Special thanks to Vlim's hint. It's the first time that I heard of this new laser welding technology. Another time Mauro and Vlim helped big time was their publication on Persian -- I realized there is no need to wait for a Persian with matching stock. That's important information.

alvin 04-02-2013 06:20 PM

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Done. Fetched it back today. I cannot be more satisfied. Scott did excellent job. Even the curved corner of the "L" was created. After some fitting work, it fits into the pistol and operates perfectly. He told me that his company has been doing micro-welding in other fields for years, now opened new service repairing gun parts.

I got a chance to look at a laser welder. It's pretty big. Looking into operator lens -- it's not unlike looking through a sniper rifle's scope, there is a cross inside, probably the intersection of those two thin lines is where laser beam goes :)

Here is the company provided the service:

http://microarcwelding.com/

cdmech 04-02-2013 08:58 PM

Wow, that is incredible!
Marc

alvin 04-03-2013 07:16 AM

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If I had known this service being so easy to access earlier, I would have tried this one: everything is perfect, except a stupid owner drilled a hole on hammer, turned it into a fake "small ring". There are numerous other examples showing people's creativity on sight as well. Those were done intentionally in the past, the parts are not really broken still being functional and can be left alone, but can be easily fixed if desired.

Olle 04-03-2013 07:35 AM

Nice job! :cheers: How quickly did they turn it around and how much did it set you back?

alvin 04-03-2013 07:52 AM

I sent it to them on Monday, and fetched it back on Tuesday. They had a few options, I told them: do whatever you can, but this lever is not replaceable so don't make the situation worse, and don't destroy or change anything on the other good reference lever. Cost me $400, roughly a new Yugo SKS.

Olle 04-03-2013 08:19 AM

Kind of pricey, but fully understandable on a job like that. Getting it done that quick is outstanding though.

alvin 04-03-2013 08:32 AM

Quote:

Originally Posted by Olle (Post 231802)
Kind of pricey, but fully understandable on a job like that. Getting it done that quick is outstanding though.

There are other options. Another way is to cut that "L" from a lever, and braze it on the base. But a scrap lever from early Mauser is hard to come, listed for sale at $150. And the brazing process still depends on a blowing torch which definitely will damage the finish on the other side. Any silver flowing into "m" or s/n will destroy the part.

For this one, they did not even cut the residual vertical part of the broken lug off. It's cleaned and melt steel is "poured" on it directly to the rough size and shape, then micro machine it. Just like Vlim and Postie suggested earlier. Experience aside, it's impossible to do this without special equipment.

===

I looked their tables and a few pieces of equipment. It's not unlike dentist. Of course, they are not working on teeth, but working on tiny metal parts :)

rhuff 04-03-2013 05:04 PM

That is an outstanding results.....you have to be pleased with it. Awesome technology!! This new stuff is expensive, as the equipment and personnel are not found on every corner. That is truly an impressive results WITHOUT damaging the part.

ithacaartist 04-03-2013 06:00 PM

Somehow I've missed hearing about this technology, and I think it's fantastic, particularly applied to irreplaceable gun parts. The work on your lever is exquisite!

I'll be doing a little TIG work on a couple of mine, somewhere down the line, but these project will be way simpler, more accessible areas, such as my progressively presbyopic peepers can handle with lots of magnification! Currently, I'm impressed by the sharp eyes and steady hands of a couple of colleagues--but these guys are about half my age

Marc, stress breaks in steel do, indeed make the exposed material look like a casting when it breaks. The stress, whether it's a constant pounding, sudden heavy shock, or repeated bending back and forth, makes the formerly steel crystalized, harder, and brittle. Cast iron is already brittle, so one good whack or deflection can kill it. The two kinds of breaks look the same because they sort of are the same.

alvin 04-03-2013 07:09 PM

Thanks for the tutorial on metal stressing.

Back a week ago, I acquired a Schnellfeuer 20-round magazine for a Spanish semi-auto pistol. The reference says that particular Spanish model can accept Mauser's magazine -- that's by design. I inserted the magazine into the gun, it did get in without problem, but it did not lock in the place firmly. With a little bit shaking, the magazine could drop out by itself! So it's not usable.

A little bit checking shows the triangle shaped locking lug on the magazine is very worn, so I had to return it back to the seller "it does not lock into the magazine well".


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