I recently purchased an old wooden walk in cooler door which I am going to use to refinish my basement. They tossed in two heavy iron hinges that were not originally on the door, but I plan to use. The jamb side of the hinge has a single hole through it with a large pin on the back.

Were these from a walk in cooler, and how do I mount them? I am guessing they were designed to be adjustable some how.

Picture at: http://www.flickr.com/photos/25775540@N03/2423436280/