source (metric) keyed shaft to replace bent one

[petertha]

If I were to find close imperial pitch equivalents of the 2 gear set, but oriented to a common 3/4" OD power shaft with 3/16" keyway...

Doh! Like pitch circles, the IMP shaft center distances would never line up to the original metric combo. I'm starting to hallucinate now.

 

[jbolt]

But the standard 3/16" keyway would have to be re-milled to 5mm key to match the one in the worm, unless I got creative there. Its a hardened gear so that leaves some Franken-key modification.

On more than one occasion I've had to modified or make a key to adapt at metric gear to a standard shaft or visa versa.

 

[petertha]

The shoulders on the flanks of the teeth show the depth of wear into the teeth. It is moderate.

I had a close look at the brass gear again. The deeper scallop looking shape (black line Bob circled) is identical on every single tooth, same side, same shape. The opposite tooth side shows almost indiscernible mild wear, from a little bit to nothing. I measured run out as best I could & its ~0.005". When I power feed, 99% of time its towards chuck direction. When I replicate this force from steel worm to brass gear, that occurs on the nil-wear side of tooth. The slight run out might then also explain only partial contact wear on the non-scallop side of tooth. Collectively this would be good news. I'm REALLY hoping I am right about this, but my interpretation is the scallop is a remnant of gear cutting & was there all along.

The other thing is, digital photos seem to really enhance surface finish. That's why my machined parts look so much worse than real life ha-ha. But even the scallops are barely discernible depth wise, at least where the worm would contact on power feeding towards tail stock. But they are there.

I wont get to test this until the power bar issue is resolved, but fingers crossed.