Hi,
I got the lock installed this afternoon. I am always impressed by folks like Mike Brooks who can install a lock in an hour or less. I've built a lot of guns but it still takes me a full afternoon to inlet a lock. I do it piecemeal, which works for me but I make no claims that way is "the" way to do it. Anyway, I mark my barrel for the vent hole but I don't drill it. Drilling the vent hole is one of the last tasks I do on a gun. I position the hole about 1/8" in font of the breech plug and usually in the middle or slightly lower on the barrel flat. Then I inlet the bolster on the lock plate so the plate will sit down on the wood. Before doing any of that , however, I trim the side panel such that I only have 1/16" extra wood needed to fit the lock. I hate inletting through a lot of excess wood.
With the plate flat on the wood, I trace it and inlet it. I using blacking to make sure it sits in the mortise evenly. The I place a close fitting drill in the tumbler hole and smack it with a hammer. That marks the tumbler position in the stock.
I center punch the mark, measure the depth of the tumbler below the lock plate, and drill a hole in the stock that depth and a little larger diameter than the spindle.
Next, I place the tumbler in the hole and trace the arc of its motion on the stock.
Then I cut away that tracing the depth of the tumbler body using a big drill, a router bit on my Dremel Destroyer, and chisels.
Then I put punch holes for the bridle screws through the lock plate, drill them to the depth of the bridle screws, and inlet the bridle.
I follow that procedure to inlet all the other parts. I use a large drill to make the hole for the sear and clear away space for the parts using chisels and my Dremel Destroyer. It does help to have inlet a certain lock before so you know what the mortise should look like. I put the mainspring in last and try to remove just enough wood for it to fit and function. I use a 1/4" drill marked for the depth of the spring to remove much of the wood. Then flat chisels and my Dremel Destroyer. Note I try to preserve as much wood as possible under the lower oblique flat of the barrel but I almost always break through to the barrel channel a little bit unless I narrow the mainspring or use a skinny barrel. If modern-made locks had taller studs that fit under the lock plate bolster such that the upper leaf of the spring is lower on the lock plate, that would not happen.
I still need to clean up some fuzzies of wood and will eventually dress up the mortise further later in the game. John Hills, like so many other early American gunsmiths probably hogged wood out of the lock mortise to get the job done quickly. I take my cue from those forgotten British musket "setter uppers" who managed much better despite making thousands of muskets quickly and cheaply.
I realized that I failed to mention the lock is a Chambers early Ketland but the plate was modified to more closely copy Hills' work. As a result, there is very little extra space at the tail of the lock.
dave
