I've been fussing for way to long to take apart a real Jacobs made in USA
41BA 3/8" keyed drill chuck. Their website says to close the jaws 1/2 way
and press on the jaws while pressing against the botttom of the shell with
clearance to allow the inside to pop out.

Tried a 1-1/2 or 2 ton arbor press. No luck. Tried a vise. No luck. Made a
fixture from steel channel and 2x 7/16x20 bolts torqued as hard as I can
with wrenches. They bent but the thing won't break free. Tried heating it,
squirting the insides with pb blaster- no dice.

I've seen some poeople press on the jaws while others press on the body
part with the key holes that the jaws slide on. Does this matter at all?

Even bigger chucks see to come apart easier from watching some youtube
videos. What the heck would be holding this thing together to hard?

Could probably take it to a place with a hydraulic press, just to see it
break apart, but I'm pretty sure this will cost as much as an exact
replacement.

Any tips?