The length of that 3/8" bolt is not critical, but you want it long enough to wedge in there easily and get it out easily. The relationship of the parts in the drwaing is not critical. I am just trying to get the concept of how it works. Weld the dogs as shown in the drawing, so that the angled portion is just even or slightly above the opening of the door.. That angle on those dogs is not critical, but should be positioned just so that when the door is shoved against them, it seals tight on the bottom. I usually keep a pair of channel lock pliers close by to smack that bolt up to lock the door closed, then smack it on the top to open it. I also use them to grab my door too.
howzat
RJ
I should have just about the whole project posted here by now eh?