Thanks for looking folks,
This is a very high quality set of castings but the lock is a challenge to build. Rolf, on the face of the plate there are two flat sections, behind the frizzen and behind the flint cock. Those allow the plate face to be clamped securely on a flat surface (wooden jig I made for lock plates, which allows the pan to hang over one side) and drilled from the back side with a drill press. I double check the surface with a level to make sure it is perpendicular to the drill. The only blind hole is for the screw holding in the mainspring. That is a challenge because there is not much thickness and you need enough threads to anchor the screw. The hole comes very close to the lock surface. In fact, you can see a little bulge on the surface of the lock where the original hole must have left a paper thin covering of steel. The other holes not showing are behind the flint cock. The rear lock bolt hole should be blind. When building this lock I made some changes from the original that will help the owner inlet the lock. For example, on the original lock, the bend of the large sear spring must be right at the edge of the plate. When installing and removing the lock from its mortice you risk having the spring wear the edge of the inlet and creating a gap. I moved the spring in from the edge a little. However, that meant I had to reshape the tumbler a little to clear the sear spring screw and slightly shorten the lower leaf of the spring. No problem, it just required a little thought. I also moved the mainspring back a little to allow more clearance for the forward lock bolt and to create a larger and stronger shelf in the mortice for the lock plate to rest on. That required reshaping the hook of the spring. I also thinned the spring a little to allow greater clearance if used with a larger fowler barrel rather than a pistol barrel. The spring has a very large bevel on the inside edge, which also will help it clear a larger barrel. I added a few degrees of preload to the spring to retain its original strength after thinning. Another nice feature is that the sear bar drops back to the same position at rest, half, and full cock. There should be no trigger rattle when using this lock. I really enjoy building all sorts of locks from different periods because each is an historical adventure and I have really begun to understand the technology and the "why" of things.
dave
