View Full Version : Need Help! 2UVR Spindle Runout

06-16-2010, 10:17 AM
When using the drill chuck the other day, I noticed that it (and/or the bit) didn't appear to be running perfectly true. I gently mounted a ground center finder in the chuck, and set up the indicator - NEARLY .010" TIR. Next came trying to determine the source of the error.

Chuck body - .010" TIR
Arbor (JT3-3/4" Straight) [near spindle] - .002" TIR
(It appears obvious that this is an axial issue, being more pronounced farther from the spindle.)

To further confirm the problem, I mounted a 3/4" endmill in the Z-collet, and checked - .002" TIR.

Hoping that I just had a bad collet, I installed a 1/2" Z-collet, and mounted a 1/2" endmill - .002" TIR.

At this point, I'm kinda starting to get a sick feeling, but I removed the collet and nut, cleaned the spindle taper and started looking/feeling for burrs. It's apparent that at some time, collets have slipped, but its not rough. I indicated on the taper inside the spindle - still .002" TIR. I also pushed on the spindle (by hand) checking for flex/play, and the indicator needle moved 5-6 thousandths.

Bearings?? New spindle or repairable?? Affordable?? :confused:

I don't have a lot of mill experience to compare against, but this mill seems to be "noisy", especially when taking a cut in the "Y" direction, more than in the "X". Nearly the same noise as when slightly rotating the spindle between the backlash in the gearing, only louder and more obnoxious when the mill is cutting (not present unloaded). Almost a tapping or pecking noise. Is this related to my TIR problem?

I just bought a Glacern Vise (AWESOME!) and a Sino 3 axis DRO (not installed yet), but am now wondering if I really should install the DRO on this mill. This will involve a lot of time and effort (especially Y axis) to install.

Any advice/guidance would be greatly appreciated.