Originally Posted by
ozzie34231
On post #88 You'll see that I only have .001" at the most and some of my measurements show only .0003"
The inside of the bushing looks pretty shiny. The shaft looks a bit weird. It's all shiny but the shine is not unidirectional, and as I've said there are inconsistencies in the diameter of about .0006".
I'll try messing with some blueing to see if that will show me anything.
Suppose the shaft is lumpy; lumps of a thou., but not across from each other, so no matter where I measure I'm never on two of them. They're small enough that the shaft fits in the bushing okay. But, when air tries to center the shaft, one or more of them presses hard against the bushing bore. Just a wild idea.
If air doesn't escape around the outside of the bushing, that part of things is exactly like yours, Ian. So if things are sealed and I still get locking, I think the problem must somehow be with the shaft.
My next experiment will be to get a small, bright light source to see if any light passes under the shaft laying on the granite plate. It's not as easy as it sounds. I have to get my eyes down near the plate and keep the light source from shining in my eyes. If I darken the room and point the light away from me and observe with a mirror I might learn a little. Or, I might not!
Making an external lap from wood to cover several inches of length of the shaft might be interesting. I can't remember what grits of lapping grease I have, maybe 250, 500, and I think I bought a small quantity of something finer. And I have wet sanding paper of every grade up to 3000. I wonder if the paper inside such a lap would work?
I just thought; I have a diamond coated sharpening block about 5 inches long.
Ozzie