Lather Run-out

I have a fairly new Fisch Mini Lathe model TC 90-100. I notice the other day that it was vibrating a little. I checked everything on the lathe to make sure nothing was loose. I started to check the front and back of the headstock. The front tip of the head stock spindle has about .010 to .015 run-out and it is about .020 to .025 at the round knob just outboard of the spindle pulley as checked with a dial indicator. These are +/- .010 as I had some trouble stabilizing the dial indicator. Any thoughts. All I have turned so far are pens. The only way I happened to notice this was cause the last pen I turned never seemed to get completely round. I sounded like I had a flat spot. The pen mandrel could be part of the problem, but I does this even when the mandrel has been removed. Any recommendations.

Thanks,

Steve

Is the runout side-to-side (radial) or in line with the spindle (axial)? Axial runout is usually easy to fix--generally, the inboard end of the spindle is held by a shoulder on the spindle nose, and the other end by either a pulley or the handwheel, which is held by a setscrew and takes up the play.

Radial runout is a problem, means something is loose or worn (bearings). .025" is pretty bad, even .010 is bad enough for spindle play. .025" is just a hair under 1/32"!

Now think about your statement on the tolerances, Steve-- +/- .010" on a measurement of .010-.015" means it could be a runout of .000 to .025! Forget the dial indicator, or stabilize it better--if you feel slop in the spindle, determine first if it's axial or radial then take it from there.

A magnetic indicator base is probably colled for here, they're around $10 and available at many different mail order tool outfits.

I'd like to say you don't have a problem, but would have to be there to be sure. If you live within an hour's drive of La Crosse, WI I'd come check it out :-) Good luck,

Ken Grunke

formatting link

Coulee Region Woodturners of SW Wisconsin

formatting link