Quote:
Originally Posted by ithacaartist
Here's another caution to consider: When bending a steel structure to and fro, forces act upon the weakest area along the length of the piece. In the case of the Luger barrel extension, this would be the square, inside corners, where each rail of the extension joins the main meat of the chamber/receiver. When flexed, and particularly if the steel is tempered a bit, this sharp corner will be the first place to show it when the steel begins to tear.
My advice is to stabilize this area with a clamp so that the area in question is not subjected to these forces. Clamping/fixing the part in place is paramount; and all deflective forces intended to realign, are best applied with a clamp, as well, for optimal control, to gently squeeeeeeze. Avoid sharp blows to the setup at all cost, even with soft or padded whackers.
Of course, the safest way is to forge/heat bend the offending arrangement back into submission. However, this would likely mean the part would need to be heat treated all over again. Metallurgically, this would be no big deal, but you'd kiss your finish goodbye, that's for sure.
I had occasion to perpetrate such a disaster upon myself a couple of weeks ago. I'd acquired a stripped frame for an Erma Ep.22 -- their second crankiest gun -- and when the upper arrived from another source, it was bent; BOTH ways. I succeeded in straightening it the hard way first, removing the dip in both rails from front to back using the clamping method to displace it just enough to overcome springback, plus a tad. Now the extension would actually slide into the frame!
My setup for straightening the length of one side, flat-ways -- theoretically the easier of the two ways it needed to move -- was deficient in stability and approach! I'd previously brought a couple of sear housings for these pistols back into true by laying them flat on a non-marring surface and tapping down the high areas with a padded instrument. However, the vibration involved in doing this with a Zamak upper was sufficient to snap off the entire extension and barrel from the side I was working on. Ouch! a $100 mistake, as it turned out... I'd attempt it again, but would use a better setup that would use a clamp instead of a dead blow hammer!
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I know what you’re saying, and work hardening is another problem. This is just a slight bend so it’s hopefully not enough to work harden the steel, but I’m sure you know that when you try and bend something back, it won’t necessarily bend in the same place. Many times, you’ll end up bending it right next to the first bend, so some heat may be necessary to prevent this.
I’m not worried about the finish though, it's going to be rebarreled and refinished anyway. By the way, the barrel has a big dent at the muzzle end, and I wouldn’t be surprised if this has something to do with the bent rail. Some people just love to use the BFH for disassembly.
BTW: I don’t agree with your statement about the Erma “Luger” being the second crankiest gun. It is the crankiest gun ever. If it’s of any consolation, I have broken some of those Zamak parts too, so my way of straightening Erma parts nowadays is to throw them away and buy new parts.
