Great, that's good news! Glad to hear you're getting close. Make sure & post some video!
Actually from what I read on bearing preload, the spindle should heat up after running at high speed for a while. That's assuming the proper amount of grease was used. Too much grease= excessive heat.
My ORAC's spindle gets very warm after 5 minutes or so at 1500 rpm and then stabilizes.
I went backwards on mine. I decided I wanted spindle reversing and got off into relays & circuits that were over my head. I got it working OK but got worried about screwing up and commanding a reversal before the spindle was fully stopped which would blow up my KB speed controller instantly.
After much hand-wringing, I stole a brand-new KBCC-125R controller on ebay. It has a built-in relay module that allows switching between forward & reverse at full speed without a whimper. It has a big ol' braking resistor that puts the whoa on the motor until it stops, then the circuitry smoothly switches direction and the motor spins back up to speed....all from one SPDT switch. Should be easy-peasy to switch it from Mach via the C-11 B.O.B. which has 2 on-board relays. I'm really stoked about it since reversing the spindle will make the front & back toolholders much easier to use.
I'm in the process of re-wiring everything to suit it as I've run out of room in the enclosure and it'll have to be mounted in a seperate box on the back of the machine.