Don't fix something that ain't broke! However, if you feel there is a good reason to take the lock apart, use screwdrivers of the proper size and fit, and before you turn a screw, put a " witness" mark to indiate its position, so you can return the screw to that mark. Then, always count the turns of the screw as you take it out. Record that. Generally, you will want to remove the mainspring first, because it is the biggest, and puts the most tension on the part of the lock. Then the sear spring comes off. Then the bridle, then remove the hammer from the tumbler by unscrewing that hammer retension screw on the outside of the lock, and using a soft mallet, tap the hammer off the square axle. Keep the hammer screw and hammer together. You can remove the sear bar, and tumbler after that. That should be as much disassembly as you need to do. Some lockplates have bolsters that are screwed on. I can't think of any reason to remove a bolster, and never have.
When you want to put it back together, reverse the order you used when taking it apart. If you lay the parts you remove out on a clean towel on your bench and mark them someway so you know what they are and where they came from, you should have no problem putting the lock back together. Take the time to clean the screws and parts. Check for signs of wearing. Sometimes you see soft steels or even iron being used in those old guns, and a part might need to be hardened to preserve it for another 100 years. When the lock is apart, that is the time to clean and polish the inside of the lock plate, first noting any place where some other part of the lock seems to be rubbing against the plate. Before polishing the lock plate, put thos parts back on the plate, so you can move them manually, and see what is rubbing, and why. File or grind, or poish off whatever is causing the rub marks, so that the part moves freely, and does not any longer contact the plate. Sometimes you will find " play" in the tumbler movement in that lock. Depending on the condition of the lock plate, and the tumbler, and how much play there is, there are different solutions to explore. You might want to talk to an experienced black powder gunsmith about fixing this problem. You want the parts to move freely, and without drag or rubbing against the lock plate, other than where they are suppose to make contact with either the lock plate, or other parts. Oil the parts before replacing them. A thin film of oil is all that is needed.
Sometimes the mainspring connect to a stirrup hanging down from the tumbler arm. Unless this is broken, don't remove the stirrup for anything. Some locks also have a small piece of metal located in the tumbler over the half **** notch. This is called the " fly " and gets its name because you have to be very careful not to lose the little thing. It seems to " fly away " if you don't pay attention. Its prupose is important: it allows the sear to pass over the half **** notch when the trigger is pulled to release the hammer from the full **** notch. Don't lose your fly.
In fact, this is the reason most of us are reluctant to take these locks apart, and why you have already received to cautionary " Whys?" from us so far. Since this is where I came in, I am done.
