Crack on rear toggle
 

I put several mags through my Thor-refinished 1917 DWM and afterward I noticed a hairline crack on the rear toggle link. I'm glad I caught it now, but it makes me sick. I know that I can probably find a new part, but is this an indication that I shouldn't be shooting 93 yr. old gun? Is this common? I wasn't shooting hot loads, just White Box Winchester from Wal-Mart. What do you guys think? Thanks.

flynt -

I am not an expert; however, I will tell you what I think.

Any metal which is subjected to repeated shocks of one kind or another will eventually experience a change in its molecular structure. The gradual change can eventually result in a crack.

I used to wonder why it was that aircraft frames were said to have a certain useful life when they were in fact made of metal. And the answer is that eventually they do develop cracks due to the stresses they experience over the years. So even an aircraft that looks perfectly serviceable can be a death trap due to these microscopic cracks.

These microscopic cracks can be detected in aircraft parts by placing them in a special dye, and then examing an X-Ray of the part in question.

And I suspect that something similar is going on with our Lugers. Fire one often enough, and eventually something is going to break. It does not mean that you abused your Luger. It simply means that it has reached the point at which metal fatigue has set in at the molecular level.

So that is my opinion; however, perhaps someone who has experience with metallurgy and/or physics can explain this better.

Not a professional either. But read somewhere they call it metal's fatigue strength.

"All metals will fail under repeatedly changing load conditions at a lower stress than they will if the load is applied steadily in one direction. A wire that might support a continuous load of 5000 MPa indefinitely will probably fail in time if a load of 3000 MPa is alternately and repeatedly imposed and then released. The piston rod on a steam locomotive is subjected to tension for a half-cycle, then to compression for a half-cycle, thousands of times every day. Structural members in a bridge are constantly subject to changing load conditions. In all such applications, fatigue strength, which is always lower than tensile strength and sometimes much lower, must be considered by a designer."

Please see page 7 of this book. Pattern matches pretty well.

Also, the metallurgy improved through the years, so a later made Mauser or Krieghoff Luger will withstand more stress.

Call Thor and ask him if he can replace your toggle... he sometimes has extra parts, and may have some that will match your finish... If he doesn't, get in touch with LugerDoc... he will have what you need...

I guess if I want a "shooter" I should get a Mauser.
Bob

Although they are moving towards collector status, VoPo DDR pistols are a good choice as well, especially when Mauser parts were used. These pistols were thoroughly overhauled in the 1950s and regularly checked during their service life. Many of these pistols were checked over and refurbished in the late 1990s when gun houses like Frankonia in Germany sold them.

But then again, one always has to take the damage of parts into account when shooting these pistols. Everyting has a shelf life, a service life and a breaking point.