Following Doug’s wise advise on soaking the door joint with penetrating oil is first on the list. I prefer PB Blaster. Do not strike the door cover as it will not transfer any shock and you will only damage it. I am only familiar with the cannonball door but their construction should be similar. It doesn’t look rusted bad and if the door was closed tight there shouldn’t be much rust in the joint especially if it was in a vault. But it is probably dry. Remember, just like sex, a little lube can get the results your looking for.
There is a narrow bit of the door that sticks out past the cover. Use a heavy brass punch and a good sized hammer to introduce some gentle shock into the door. If you use a steel punch you will cause dents in the steel. Adding some pressure to the crank while doing it may help. Do not put excessive pressure on the crank as it is cast and can break. Never hit a crank with a hammer. Either can also break a tooth on the ring or pinion gear or shear the key way on the pinion gear.
If that doesn’t work you can unscrew the door pivot finials and remove the square headed lock bolts (top and bottom), you can screw out the pivot bolts. Penetrating oil is important here too. If I remember correctly, Victor pivot bolts are hex head, if they are slotted be sure to use a correct sized slotted socket bit. If the bolts are stuck be careful not to spread the head if it is slotted. Once those pivot bolts are out there are a few small bolts around the side of the door cover. Once they are removed the cover can be removed.
Then the door will be exposed and you can have some areas to hit will the mall. Be careful not to damage the ring gear. I would hold some thing against the door and strike that. Be gentle! If there is a time lock on the other side you don’t want to be sending shock wave into it.
If you do pull the door cover the door will need to be readjusted with the door pivot bolts. Keep us posted with your results and please add lots of pictures of the door parts, body, inside, and the time lock (if equipped). We like pictures.
Here is what a cannonball door looks like under the cover.
