Craftsman model 113.21861 Cast Iron Jointer

by Mike
(Virginia)

I received this jointer and corresponding motor (without the stand) from a neighbor and have a question about it. It has a knob on the right side that appears to adjust the depth of cut for the wood, however, the knob on mine won't turn. I'm wondering if it is frozen and needs oil, or there's a release or something I'm not aware of that I have to operate before the knob will turn. If anyone has any information about this it would be greatly appreciated. Thanks.