Bridgeport Spindle Questions

Hi all,

I've been happily cutting (lots of) chips with my CNC'd BP clone with
the variable speed head and now am noticing a strange smell,
particularly during heavy cuts and a lot more rattly spindle (internal)
noise most of the time. I don't think it is a bearing problem because I
measured the runout and it is still negligible according to my .0005"
dial gauge and cutting quality is still excellent. I visually checked
the big belt and it looks ok but I now have about 800 -1000 hours on the
unit (bought new) and was wondering what is the typical belt life? FYI,
the motor is run from a VFD at 75 Hz and the spindle actually runs at
about 4500 rpm and I adjust my feed rates to get best cutting results.
Also, every day I wind the vari-speed dial to low and allow things to
warm up before going up to the higher speed.

As I have CNC'd the knee, I have the quill locked 99% of the time. I
have never used any of the quill auto feed levers or back gears. Has
anyone experimented with removing some of the parts behind the various
lever/access panels to reduce the number of moving parts and hence
reduce the spindle noise level?

TIA, Cheers, Peter