Crack on rear toggle

flynt · 05-01-2010, 07:07 PM

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.

Mauser720 · 05-01-2010, 07:21 PM

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.

alvin · 05-01-2010, 07:39 PM

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.

MFC · 05-01-2010, 11:39 PM

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

John Sabato · 05-02-2010, 10:49 AM

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...

OIF2 · 05-02-2010, 12:53 PM

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

Vlim · 05-02-2010, 01:21 PM

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.

05-01-2010, 07:07 PM	#1
flynt User Join Date: Jul 2007 Location: Dallas-Ft. Worth Metroplex Posts: 6 Thanks: 3 Thanked 1 Time in 1 Post	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.

05-01-2010, 07:21 PM	#2
Mauser720 User Join Date: Aug 2007 Location: Kansas Posts: 535 Thanks: 18 Thanked 49 Times in 33 Posts	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. __________________ Mauser720 - Ron "Those who do not know history are doomed to repeat it."

05-01-2010, 11:39 PM	#4
MFC User Join Date: Sep 2006 Location: Louisiana Posts: 1,237 Thanks: 183 Thanked 281 Times in 162 Posts	Also, the metallurgy improved through the years, so a later made Mauser or Krieghoff Luger will withstand more stress. __________________ Mike C.

05-02-2010, 10:49 AM	#5
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,156 Thanks: 3,003 Thanked 2,308 Times in 1,098 Posts	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... __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

05-01-2010, 07:39 PM	#3
alvin User Join Date: Jul 2007 Location: US Posts: 3,843 Thanks: 132 Thanked 729 Times in 438 Posts	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.

05-02-2010, 12:53 PM	#6
OIF2 User Join Date: Apr 2010 Location: TEXAS Posts: 83 Thanks: 133 Thanked 73 Times in 25 Posts	I guess if I want a "shooter" I should get a Mauser. Bob

05-02-2010, 01:21 PM	#7
Vlim Moderator Lifetime LugerForum Patron Join Date: Oct 2002 Location: Europe Posts: 5,053 Thanks: 1,036 Thanked 3,990 Times in 1,205 Posts	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.