Yeah, if I was using the drill, I'd slip a piece of tubing over the stem, then chuck on that.
I do have some lapping compound, 220 and 400 grit, And oh yeah, silicon carbide, so it has to be cleaned out well.
Really, the only thing left in the engine are the piston rings and the cam, crank, and rod bearings.
The parts were expensive, I could've saved a bit on shipping, maybe. I went OE for all critical stuff. I did have to get a couple tools, too....lol.
I think there is roughness, but from carbon buildup. I'm trying to go slow and steady, so my labor hours I'll never recoup. It is what it is.
I'm gonna fix it or die trying.