My Spindle Isn't Worn Out
Collets are Consumable

For the last month or so I started noticing alignment pin holes that are
spiral interpolated on one of my machines were a little loose. Press fit pin
holes were getting to where I could press them in with my thumb. That's a
bad thing. Those little high speed spindles have a finite life and that one
is a year old. I don't think it has the 6000hrs advertised for the bearings,
but it might be getting close, and honestly I usually get more than 6000hrs
out of them Still to be that loose I thought I'd be able to "feel" slop in
them when the spindle was cold first thing in the morning. No slop. Ok, how
about a runout test. Not much. Much less than 1/2 thou. Maybe 2-3 tenths.
Now to be fair I did a runout test with a dowel pin in a 1/4 inch collet.
Then I set up the indicator to measure travel backlash in the table. Nope
still just a hair under half thou, and that would make smaller holes not
larger. Finally I looked at the little 1/8 inch collet that was holding the
1/8 SE mill that was making the oversize holes. Or rather I took a fresh new
one out of the package and cut a mold. Perfect. Everything is back to
normal. I have to use the arbor press to set pins again. That collet has
outlasted one spindle, has thousands of hours on this one, and has probably
pushed more than a couple small end mills to the breaking point. I guess I
can't complain about a very cheap Chinese ER16 collet. Collets are
consumable.