….and darken the solder with a touch of Solder Black…and the result is marginal. The relatively loose threaded joint shows a rather wide band of solder impossible to completely hide. I’ll redo this later using another filling technique shown below.

Moving on to the rats nest of holes in the receiver, I chase the threads with taps to expose fresh metal and degrease and clean them thoroughly with trichloroethylene solvent.

I could thread some #6 and #8 screw blanks and solder them in as was done with the sling swivel above….and if strength is important, this is the preferred technique. On this particular rifle firing cartridges of relatively low pressure, strength isn’t as important and I’ll concentrate on cosmetics instead.

I cut some screw blanks to serve as unthreaded plugs and put a sharp taper on them using my “lathe”….I have access to commercial metal lathes but spinning them chucked in the electric drill against the disk sander is fast and works just as well.

Then I simply dip them in solder flux and drive them into the holes for a tight fit, crushing the female threads in the process. This will provide as small a joint line as can be made. Chalk is applied to catch any finish-destroying flux and solder runs, and I heat the receiver slowly to 475 degrees and apply a mere drop of soft, high-strength solder, working the solder and flux around my joints using a dental pick.

Will this be strong enough? The solder I’m using contains 4 pct silver and 96 pct tin that offers 28,000 psi of strength and is resistant to all finishing processes normally applied to firearms. I could gain more strength…38,000 psi… by using a higher silver content solder that requires 650 degrees of heat, or 40,000+ psi using 1100 degree silver braze. I also could fill these holes with nickel steel rod by gas welding, or take it to a friend skilled with a TIG welder….all at higher temperatures.

My problem with higher temperatures is that I have only a poor idea of how that critical receiver steel was hardened and tempered to withstand the 35,000-psi its cartridge generates in the barrel chamber….the pressure area held together by the critical barrel-receiver threads immediately below one of my holes. The steel seems soft, or at best case or surface hardened, but I do know that much over 600 degrees of heat will ruin whatever temper the steel has and I choose not to risk more heat.

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