Mini-lathe tailstock adjuster with differential screw

[homebrewed]

Looking good! Nice execution, and it should serve you well.

 

[WobblyHand]

Got to use this today. I drilled out the vertical tightening screw with a 5 mm drill in the mill. Made a small nut out of 1/2" hex stock. Milled it to just fit the 12 mm slot. At the moment, the curvature of the end of the slot limits the travel, but it is good enough to be able to do a lot of adjustment. Adjusted the differential screw for horizontal offset. Got terribly confused when initially trying it, as the adjustment seemed backwards, but figured it out. Standing on the same side as the adjustment (back side of lathe) seemed to help the brain to figure it out. At one point I put in shims on the base, but I don't need them, there is more than enough clearance. If I were to do this again, I'd make the knob bigger, 5/8" is a little small. Probably make the knob out of steel as well with a larger set screw. M3 in brass, is not so good. The set screw seems to slightly loosen. More binding of the screw than I'd like - which came from transfer punches that did not match the holes well enough. But it has served its purpose, I'm partially back in business...

This is step 1 of fixing the tailstock. There is quite a bit of vertical offset, but it is small enough that I can use the tailstock to drill holes with a #29 drill. The offset is too large to consider using a #40, or smaller, but at least I can use the tailstock again for larger drills.

Ok, now I can at least make my spacers... #29 drill. 8-32 threads cut with spiral point tap. My goodness, what a pleasure to use a spiral point tap as compared to a normal one. No chip breaking required. Go straight in. Chips self evacuate. Steel was 1144. Back to my list of projects...