Originally Posted by Johno59

I'm impressed that folks can tell that the bearing race of a fixed cup isn't damaged/worn out from looking from the drive side into the BB abyss. Putting new ball-bearing in a worn out race will not improve anything.
The advice to do the fixed first is very sound. The rigid spindle acts as a fulcrum as your tool bares down on the shoulder of the raised portion of the bearing face. This way all the force is contained within the BB shell which is very tough - unlike a frame's seatpost, crossbar etc secured in a vice.
The use of a Jimmy bar is likely to damage the frame so I would avoid it.
Hoping lubricant will creep into a 40mm thread that has been stuck solid for 10,20,...50 years is delusional.
Heat works but only if your tooling up can apply maximum mechanical force and the paint work is of no concern.
The tightening bolt approach just slips uselessly in my experience, as well as crushing the race.
The moral of the tale - lube everything once a year and these components will turn out with little effort and in doing so, they'll outlive you.