Working on a stem for a project. Closest fit was pretty perfect in the winding section, but had a 1.4 thread. Thought grind it down, undersize it and even though the stem is hardened I’d just get enough in a 1.2 tap crown to catch. How hard could it be…
How wrong was I. Broke three of the little b*****ds. Didn’t go near the end, but just vibration from the grinding wheel broke the thin section.
But…
I had a 1.2 to 0.9 adapter. I drilled out the threads added some silver solder paste, fired up the gas torch, then quenched it to keep the hardeness.
Easy to grind in a slight recess for the setting screw, this is a pin set movement, so it just holds it in place, it is a dip in the diameter rather than a hard step.
Job done…