"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70...
"PrecisionmachinisT" fired this volley in
news:_MOdnYD1kPHGxDTSnZ2dnUVZ_sSdnZ2d@scnresearch. com:

Also, you might be surprised at how accurately most new, medium
quality, 3 jaws will repeat out-of box up until they finally get
whacked a good one.

I own that exact chuck. TIR ain't all that good.


Usually, I make the boss on the backing plate a tad undersize....allows a few thou of radial clearance between it and the chuck body--then, when I mount the chuck, I use an indicator and tap it around so as to carefully position it dead true to the spindle bearings before finally tightening the mounting bolts....finally, I'll use a ring and then a spider, grinding the master jaws with a tool post grinder, in two stages.

This does two things...

First, it balances the chuck which, if it happens to on a lathe, keeps it from shaking up your beer and walking across the floor when run at high speeds...

Second, this leaves you with a bit of a a kludge factor, allowing you to bump it around a little in case it's only accurate within a certain size ranges ( damaged scroll ) or where it's taken a substantial hit, but you don't currently have time to go back and re-grind your jaws at the moment.