Dial Calipers & Self-Centering Chucks

Dial Calipers & Self-Centering Chucks

I mentioned a few days ago that because I had bought a 4 jaw chuck (which doesn't self-center workpieces), I had been forced to put together something to hold a dial indicator in position, so that I could more precisely center the workpiece.

I also mentioned some months back that squaring the ends of a cylinder on the lathe is a bit of challenge if you aren't pretty close to a right angle when the workpiece comes out of the chop saw. But even with the greatest care in setting the angle on the chop saw, it is still a bit of a struggle. You can get a cylinder square by trimming one end, then the other, each time getting a bit closer to truly square. But this is slow, and you end up wasting a lot of material that way, since it may take several times through to get acceptably square.

So I put my dial indicator assembly to work with the self-centering 3 jaw chuck that I normally use for squaring workpieces for ScopeRoller. This made it possible to center the workpiece within about .010" very quickly (with gentle little taps on the end until I reached that goal). After trimming both ends, I had .002" accuracy on squaring, and it greatly simplified centering holes.