1897 Project No. 1

[ssgross]

I've been at that buggered screw all weekend long.
First attempt...what little slot was left I deepened with a needle tip diamond abrasive tool on my dremmel. It worked to deepen the slot, but no go on backing the screw out.
Next attempt, drill a 1.5mm pilot with a center drill on the drill press. Measuring the other screw, if I stop just shy of the taper, I should have the threaded part of the screw with a hole in it, and weakened the pin part to where it will break easily. Worked like a charm. Couple light taps with a brass punch on the back of the chamber ring, and the pin sheared off, leaving the screw in the hole to be dealt with. The fragment of pin has a dimple from the drill dead center. Way to go my hole is centered!
here is what the screw looks like for reference...


Next attempt, with a t6 screwdriver bit in the drill press, press it in and rotate the chuck. The edges bit into the hole well enough, but didn't back out the screw. just tore up the hole. Still, there is plenty of meat left on the screw and the original threads are undamaged.

Last resort now, clean out the screw as best I can, and chase the threads with a tap. What threads are it? Now it gets interesting. The other hole appears to be tapped all the way through, but the screw does not pass through. I bet they tapped with a plug, but not deep enough so the bottom threads are too narrow. The screw is 0.118 in major diameter, which isn't on any chart. The closest thing in an m3. Well, I had one and the m3 screw goes all the way in, but I can't even start the winchester screw into a m3 nut, which I had too. After digging out a magnifying glass and a pitch gauge, I think I'm looking at a 40 TPI screw? I don't have a 44 or 48 gauge. The diameter is too big to be 6-40 (verified by tapping a scrap of aluminum), and too small to be 5-40,44...but of course I don't have a set of #5 taps to try. Oh well, it'll be next weekend before I can try again, just enough time to get taps in the mail. At least my hole is clean, centered, and ready to go.