Scottish Pistol Part IV: Lock Mechanism.

The summer of 2009 was the 3rd year of our Scottish Pistol Masterpiece Project. The 4 smiths working on the project had completed a barrel the previous summer, with the finish work occurring over the winter. Now it was time to make the flintlock mechanism for the pistol.

The lock mechanism is both complex and finely fitted. Every part was forged from wrought iron bar or steel. For this style of pistol, the lock plate has a standard shape, but not a set size. The forged and filed lock plate is fitted precisely to the forged and filed stock.  The internal parts of the mechanism are forged from iron bar and then filed to shape as well.  Here are rough forgings for the springs.

The end result needs to fit so precisely that engraving can flow over the stock and right onto the lock plate as if it were only one piece of metal.  The pivot points were located and drilled. Then work began on making all of the parts.  Illustrations of how a flint lock mechanism works can be seen at here.

On the outside of the lock mechanism are the hammer, the pan, the frizzen, and the frizzen spring.

Another array of parts are located on the inside of the lock plate and are responsible for making the hammer fall when the trigger is pulled. The sear and sear spring connect the trigger to the hammer mechanism. The sear’s job is to prevent the hammer from being actuated until the trigger has been pulled. Once the sear is tripped, the mainspring throws the hammer and flint forward into the frizzen, and hopefully creates sparks that fire the powder in the pan and the main charge in the pistol.

Each of these parts has been forged from wrought iron or steel. The rough forging is shaped to the final size in a long, slow, painstaking process using files. Sometimes it isn’t clear how to best forge the piece. In that case several methods and multiple blanks are forged until one is close enough to create the final part.

Creating the lock for the pistol is a very challenging project. The shape of each part and the location of each mounting hole and each screw effects every other part. Changing the shape of a sear, hammer, or spring by 1/32th of an inch can make the difference between a pistol that fires and one that doesn’t.  The Scottish Pistol Project has been an exciting chance to research and build a lock using the same materials and tools as  the Gunsmiths in Doane, Scotland in 1740.