View Full Version : Optical Centering Device in a Lathe

01-23-2008, 05:02 PM
I have an optical aligment scope that fits into the spindle of the mill and is used to center work. I was thinking of using it to center odd size pieces in a 4 jaw chuck on the lathe. The spindle end of the optical scope can be mounted in the tailstock mounted Jacobs chuck and moved close enough to focus on the marked center point on the piece in the 4 jaw chuck. The movement of the part is done with adjustment of the jaws and the movement checked with the scope. One advantage is that the scope does not need to be rotated as in the mill as the piece rotates when the chuck is turned. Does anyone see problems with this idea? Thank.


01-23-2008, 05:12 PM
Only immediate problem I see is the centering scope might not be centered when held in a Jacobs chuck in the tailstock. easy enough to check, put a center in the headstock end and true it, then check the scope indicates its central.


01-23-2008, 05:25 PM
A wiggler is quicker and easier.

01-23-2008, 06:13 PM
I use my eyes and a small hammer . Close counts on most things.

bending over to use an optical device sounds less than good for the back. I would just grab a mag base and indicator and save myself some pain.

Lew Hartswick
01-23-2008, 06:40 PM
That may be a good way to adjust the tailstock to center on the
spindle also. Wish I had one of those to try it with.

01-23-2008, 06:53 PM
Take a piece of stiff wire about a foot long, music wire is good. Also find an inch or so of rubber gas line hose. Poke the wire through the hose and slip the hose over the tool bit so that it lies in line with the lathe axis. Using the carriage and cross feed stick one end of the wire (wiggler, shop made style) into the center punch mark on the work in the 4 jaw. The rubber hose acts as a swivel point and the free end of the wire will describe an arc as the chuck is turned if the center pop is off center. By making the piece of wire between the work and the rubber hose much shorter than the free end the motion will be greatly amplified. You can easily get it centered to within a few thou or better this way. Same trick can be used to feel the action on parts that can't be reached with an ordinary indicator.

01-23-2008, 09:54 PM
Sounds like a good idea. I have an optical centering scope. I use it for making measurements since I do not have an optical comparator.