How to fix a bent barrel extension?

[sheepherder]

Originally Posted by Olle

It's about 1/8" off at the very end, and it seems to be bent right behind the chamber.

Do you mean the 'fork' is bent-in one hundred and twenty-five thousandths??? That should show up on a picture pretty good, but I don't see it...

I've had a twisted and Z'd Luger extension back in the 80's...Took a long time to get it straight...Months, maybe even a year...Nudging it a bit more every couple days...When I was done, It was straight again, and I looked at it and proudly said...

















NEVER AGAIN!!!

Box yours up and ship it off to Gerry Tomek.

[Olle]

Originally Posted by postino

Do you mean the 'fork' is bent-in one hundred and twenty-five thousandths??? That should show up on a picture pretty good, but I don't see it...

I've had a twisted and Z'd Luger extension back in the 80's...Took a long time to get it straight...Months, maybe even a year...Nudging it a bit more every couple days...When I was done, It was straight again, and I looked at it and proudly said...

















NEVER AGAIN!!!

Box yours up and ship it off to Gerry Tomek.

I measured with calipers and it's more like 3/32", 0.095" to be exact. You can't really see it in the picture, but the right rail is bent pretty bad.

The left rail appears to be straight, so I was thinking along the same lines as GT: Clamp it in some kind of fixture, then bend it a tad over to allow for springback. What I had in mind was to clamp the left rail to a straight surface, and also clamp the chamber really tight to make sure that the left rail won't bend. The next step would be to fabricate a small machinist's jack, set up a dial indicator and start spreading it about 1" or so behind the chamber. Spread it a bit, take a reading, check the result, spread a bit more, take a reading, rinse and repeat until it's straight. A slight "Z" won't bother me all that much, this will be refinished anyway so I'd rather file/polish the last few 1/1000 than working it until it cracks.

Then again: I might chicken out and I need for someone to remove the barrel as well, so are you up to the challenge, GT?

[G.T.]

Sure thing! I'll certainly give it a go.... But, send the toggle train with! Best to you guys, til...lat'r....GT

[Olle]

Originally Posted by G.T.

Sure thing! I'll certainly give it a go.... But, send the toggle train with! Best to you guys, til...lat'r....GT

GT,

You have a PM...

[sheepherder]

Originally Posted by Olle

A slight "Z" won't bother me all that much...

...Until you try to put the toggle axle pin in...It's pretty much a precise fit...

Part of the problem with 'spreading' the sides is that both sides want to spread at the same time whether you support them or not...I toyed with the idea of making a special mandrel to insert into the receiver, with a drilled & aligned hole for a 8.82mm rod that would enter the barrel...Then you could work on 'spreading' the sides one at a time...

I do have a brass receiver insert for my barrel swaps; in an emergency (which is doubtful in my future) I could drill it and insert a squib rod to make a shade-tree fixture...But that axle pin is the most oddball size ever designed; not Metric and not Yankee...Not Inch, not Letter size, not Number size...You'd have to make up a special pin (or use a spare axle pin) to test your alignment after every tweak...

...Or just box it up and send it to Gerry!!!

[Olle]

Originally Posted by postino

...Until you try to put the toggle axle pin in...It's pretty much a precise fit...

Part of the problem with 'spreading' the sides is that both sides want to spread at the same time whether you support them or not...I toyed with the idea of making a special mandrel to insert into the receiver, with a drilled & aligned hole for a 8.82mm rod that would enter the barrel...Then you could work on 'spreading' the sides one at a time...

I do have a brass receiver insert for my barrel swaps; in an emergency (which is doubtful in my future) I could drill it and insert a squib rod to make a shade-tree fixture...But that axle pin is the most oddball size ever designed; not Metric and not Yankee...Not Inch, not Letter size, not Number size...You'd have to make up a special pin (or use a spare axle pin) to test your alignment after every tweak...

...Or just box it up and send it to Gerry!!!

I was thinking about supporting and clamping the barrel, instead of using a rod in the bore. If you lay it flat on its side and clamp it both at the muzzle end and right at the chamber, you would only be bending one rail... or?

But yeah, boxing it up and sending it to Gerry sounds like a safer alternative.

[sheepherder]

Originally Posted by Olle

I was thinking about supporting and clamping the barrel, instead of using a rod in the bore. If you lay it flat on its side and clamp it both at the muzzle end and right at the chamber, you would only be bending one rail...

Just out of curiosity, where do you intend to apply pressure on the rail to bend it???

BTW, is there an amusing story behind how this rail got bent???

(Mine got bent when I removed the barrel without proper tools)...

[Olle]

Originally Posted by postino

Just out of curiosity, where do you intend to apply pressure on the rail to bend it???

BTW, is there an amusing story behind how this rail got bent???

(Mine got bent when I removed the barrel without proper tools)...

My approach would be to lay it with the left side down on a fixture (for example, a heavy aluminum block) and clamp the barrel, the chamber and the left rail securely. This would leave the right rail unsupported. Then I would insert a machinist's jack between the rails and push, while reading with a dial indicator at the end of the rail. I can make a spacer block (using another Luger to get the correct dimension) to get a fairly accurate base reading for the indicator, then I'd push beyond that a bit.

After doing this in increments a few times, I should get a pretty good idea of the springback. After the final push, it should spring back to the base reading. I'm sure there will be some fine tuning after that, but this should get it back within reasonable tolerances. Well, that's what I had envisioned anyway.

It was bent when I got it so I really don't know what happened to it, but it takes a lot of force to get a breech block in between the rails so somebody must have squeezed it pretty darn good. There are some bad diagonal gouges on the rails, almost like the extension has "derailed" at some point, and I'm sure that this has something to do with it. I might even take it to a machine shop to have it crack tested before I go any further, I definitely don't want it to break.