What shit is that you may wonder? The wholly inappropriate use of welding to "repair" lockwork parts. Regardless of how good an idea you may think it is, notwithstanding that "everybody" does it and, regardless of who says it's okay to do, WELDING ON HIGH-CARBON, OIL-HARDENING parts is NOT a good idea!
Just because these parts are steel does not mean that they are suitable for welding! All steels are NOT necessarily weldable! The higher a steel's carbon content, the less suitable it is for welding, at least the type of welding that is practiced by most "practitioners of the gunsmithing arts" (IE, hacks) in the business today. Steels with a carbon content above about 40 points (that's 4/10ths of 1 percent) require special procedures for welding successfully. Some of those special procedures include pre-heat, post-heat, VERY specific filler materials (some materials can only be successfully welded using the same alloy as the parent material), specific heating and cooling rates, etc. Most of the lockwork parts in these old guns are made of oil-hardening, plain steels like 1075 or 1095 that contain anywhere between 6/10ths and a bit over a full percent of carbon. This makes them, for all practical purposes, unweldable by the typical gunsmiff with a TIG welder that he barely knows how to turn on. Oh sure, you CAN weld the parts and they might even look good. Hell, they might even hold up for a hundred or maybe even two hundred cycles but, THEY WILL FAIL. I can't tell you how many failed hammer notches, sear noses, bolts, tumblers and even springs I've seen that were "repaired" by welding. They all fail in exactly the same way, with the weld portion cleanly separating from the parent metal, right along the weld seam. Here's a good rule of thumb, if it's a through-hardened part, don't weld it. Here's another, if it's a case-hardened part, ANNEAL the !@#$%ing thing before you weld it. And NO, you can't anneal it in your kitchen oven. The ONLY correct way to repair a part of this type is to replace it. If no replacement is available, then you make one. If you can't do that, don't call yourself a gunsmith because you're not. Owning a TIG welder doesn't make you a weldor any more than having a Brownell's catalog makes you a gunsmith. The very least you can do is attempt to know the materials with which you're working and act accordingly. The client is paying for your knowledge, you should at least make an attempt at having some. Welding is a career/science unto itself that, like any other complex
endeavor, can take a lifetime to master. If you think that welding up
half a dozen or so parts a year makes you a weldor, you might want to
rethink that. Welding is also a very valuable component of gunmaking, when properly executed and where it is appropriate.
If, by some chance this is seen by any of the vandals that committed the acts shown below and you are offended: GOOD.
A mainspring that had been welded, along with its replacement
Cracked weld "repair" of Fox sear nose
An Ithaca Knick sear nose with failed weld "repair"
Birdshit welded tumbler
Here's some truly vile work