The Adams Rite 2331 deadbolt accepts a mortise cylinder or thumbturn on either side. What's unique about it is that when the bolt is fully thrown, two stainless steel hooks extend out of the bolt and hook in to the strike plate. It is meant for sliding pocket doors, as the hooks keep the doors locked together. But I imagine that this bolt could be used on any door as a way to prevent spreading. What I love about this lock is its mechanical simplicity. Let's take a look inside.
Here we have the cover off, with the bolt thrown.
And here with the bolt retracted. Notice how the tailpiece of the mortise cylinder or thumbturn drives the bolt with a gear.
Here is the drive gear and bolt removed.
A close up of the bolt. When the steel tabs you can see here are pushed against the inside of the lock case, the steel hooks are pushed out of the bolt.
And the bolt disassembled. My fingers and camera are fully covered in grease at this point.
Now, disassembling this lock is easy. Putting it back together again is another story. Reassembling the bolt was tricky enough, as there is a little spring inside the bolt that needs to be held out of the way while the gear piece is put back in place. But the real headache was getting the timing of the gears just right. The first time I took apart this lock, I didn't have photos to reference while reassembling, and it took a lot of trial and error to get the timing of the gears right so that the mortise cylinder and thumbturn would function correctly. If the gears are out of alignment by just a single tooth, the lock does not seem to work correctly. This is how the timing should look. Fortunately, I don't imagine there being many situations where you would ever need to actually open up the lock case. Hope you enjoyed reading.
Now there is yet another lock type I need to find for my collection. Oh well, the collection must grow. 
