I'm getting ready to run a project which needs a 1/32" EM. I've done some work with them before, and had good results. But having just replaced my spindle, I though I'd check the runout for giggles.
With no collet installed, not even the R8 collet, I measured 0.0002" runout on the spindle. Pretty good I thought. I then installed the R8 TTS collet again, inserted a ER20 holder, 1/8" ER20 collet, and 1/32" EM (carbide with 1/8" shank). The runout on the tool shank (about 1/4" from the holder) was about 0.0011". Rotating the holder in the R8 collet didn't change anything.
So at this point I'm trying to figure out where the runout is coming from. So I removed the bit and ER20 collet, but left the holder in the spindle. Same runout. I tried an older ER20 holder (pre-TTS) and had about 0.0014" runout.
I doesn't seem to matter if I rotate the holder 180 or 90 deg in the R8 collet.
Time ran out and I left for the day, but it got me musing about where the runout is coming from. Since turning it in the R8 collet didn't really change things, that implies that it's not particularly the cumulative runout of R8 collet and tool holder. So that means the runout is either in the R8 or in the ER20 holder?
I guess I'm just cutting with one tooth on that EM, unless I track it down. :-)