"DonkeyHody" wrote in message ...
Today, after running it for about 30 minutes with a 3/8
round over bit on some cypress, the collet nut was too hot to hold.
The bit was a brand new Whiteside, and it never loaded the motor, so I
suspect the heat came up from the router bearing instead of down from
the bit. I've never had a collet nut burn me before.

That makes no sense to me. If the motor was never loaded the bearings are
probably just fine. 30 minutes of cutting wood will generate a lot of
friction and friction generates heat and the heat will travel the path of
least resistance. That would be down the shaft and into the collet nut that
makes a good heatsink.

Did you grab the housing? Was it warmer near the top or was the collet nut
hotter than the motor housing? How hot was the bit?
Ed