I was surprised too, seems the critical temperature is 125c no more, i also blew air down the spindle to try keeping it cooler.
No damage, no sweat and all parts reusable.
To reassemble, I borrowed a baking tray from the cook room
wrapped the bearings in tinfoil, set my powder-coat oven to 120c, put a lump of 1/4" scrap steel on the tray, bearings on top and gave it 20 minutes.
I mounted the spindle vertically in the vise, gripping on the drive dogs, donned a pair of welding gloves and the bearings just fell on, no hint of pressure needed. I realigned the little "o" marks on the inner and outer races and also between top/bottom bearings, tightened the locking ring and left to cool, retightened and lock-tabbed it.
These were original bearings, specially ground and marked with codes, the tubes were measured and both were equal.
Spindle feels very smooth and is now wrapped in cling-film awaiting fitting.
I need to make a drawbar - one piece or two joined ?? Its a hell of a lot of turning if one piece
Anyone know what thread is in a BT30 holder??