OK let's see if I did this right. For the nod I used both a 0.001 dial indicator, and a 0.0005 DTI. I set the depth of the .001 DI, and zeroed on the outside edge, and swept it to the inside edge. There is a 0.003 runout. with the 0.0005 DTI same procedure it was 0.0025. Would this be accurate, and worth fixing?
Technically speaking, in my view of things, that's too far out; but.... for now, you might want to consider other things. I'm going to assume you do most of your work using a vise. Mount your vice and get a 6" long, 1/2" thick parallel known to be in good condition. Stand it up vertically in the vise. Use a piece of copper wire or tig rod etc between the parallel and front jaw and snug the vise so the parallel is kept flat against the rear jaw of the vise. (Let us know if this is not making sense). Now, use your indicator and check the up/down (Z) travel runout by cranking the head up/down (don't use the spindle crank). Check an up/down distance of about 3-4 inches.
Ideally, the table should be flat and your vise's rear jaw should be perpendicular to the table. If your vise is out a little and so is your table, you need to check error stack-up. It could be that, for most of the working distances you operate at, the errors collectively cancel out, or, they combine and make things much worse off.
Once again, it's
best if everything can be perfect (both table and vise) but, we don't always have what we want. I'm also mentioning this so you understand all the different factors at play.
FWIW, I try to get my table within +/- 0.0005" over an 8" circle. When I do the vertical test, it's also within +/- 0.0005". Last but not least, my PM45 has only needed adjustment twice in the 7-8 years I've had it. The first time was when I made an adjustment using a piece of junk vise. The second adjustment was made when I purchased a half-decent vise. Other than that, once nod is properly adjusted, it's pretty hard to knock it out of whack.
Regards
Ray C.
