Out of Round with a Dial Indicator

Hello I have a Craftsman dial indicator that has a magnetic base and I have been fastening it to the carriage and testing the 3 jaw chuck, 4 jaw chuck and the plain spindle of the head. The 3 jaw chuck was off by about 5 thousandths, the 4 jaw chuck was the worst with about 1/100 of an inch, and the spindle was the best in about only 1 thousandth of an inch out of round off.

Does anyone know how to straighten the out of round in the head spindle? I heard it is adjustable.

I got the Technical Books from Lindsay and they have a lot in there about engines. I like engines. Maybe I'll build an engine. Does anyone know if you can build an engine with only a lathe and a drill press (and not a milling machine)?

God Bless everyone.
And thank you for your help.
David Williams
Bye

Is the 4-jaw independant?You may be able to adjust each jaw by itself to dial it in to near zero.

The 3-jaw may be able to move a bit on it's mounting plate, or at worst have the jaws reground.

However the spindle must run true. While there are adjustments, nothing for out of round.

David, where are you making your readings? Are you talking about runout measured on the OD of the chuck bodies? Assuming the spindle itself has a morse taper hole, the best place to see whether the spindle is running true is to indicate on the spindle bore.

Correct, measure the spindle bore with the indicator needle as close to parallel to direction of rotation as possible. This should remove any indicator chucking. If your spindle still shows out of round, it is probably due to bearing damage or wear. Sometimes new bearings will fix this but sometimes it also requires getting the bore reground. Hope this helps.

Unless you are doing some extremely precise parts, you can live with .001" runout. Usually if you want something to run true in a lathe you bore soft jaws anyway. Problem solved.