It looks like what I lack, and sorely need, is a "Destruction Manual" for my
1J Bridgeport.

There's been a severe rattle coming from the upper housing for a while.
Judging by past posts, this is likely a problem in the backgear housing. So
I've taken off the belt housing and now have the backgear housing completely
off, but can't go further. It seems like the bullgear and the splined hub
are held in place by this big locknnut (called "N-08 Special 5/16" Thick
Bearing Locknut:") which is over 2" wide on the OD, and looks like it can be
driven off with a spanner wrench - only I've found that it won't come off
that way. I've peeled back the lock washer tabs and have been soaking it
in penetrating oil for two days now, but no luck.

Is there some secret to getting this thing off?

-- Hugh

P.S. I don't think it's rusted on - There's no rust anywhere in the head.