Here are a few thoughts from a CNC machinist and a lock builder.
Back in 2004, when I was just getting into machining, I asked Jim Chambers why there weren't any cnc'd locks or lock parts available. His basic answer was, price. The industry has changed a lot in the ensuing 15 years. For example, one of the machine shops I worked in used to have about 50 men on the payroll working 3 shifts around the clock. By the time I started there, the same output only needed 15 men, working 2 shifts. The price to manufacture many flintlock parts in the basically "small" quantities this industry requires, has started to become more economically feasible.
At this point in time there are three main categories of lock manufacture. They include Cast, Hybrid (using both cast and cnc'd parts) and fully CNC'd. (I am purposely leaving out custom and hand forged locks here)
Everyone in this hobby knows cast locks as they account for the majority of locks. Casting is relatively inexpensive (comparatively anyhow) but secondary operations to prep and assemble can be quite time consuming.
Hybrid locks are logically the next step. Improving the precision of some of the internal parts via cnc has many advantages. Increased interchangability, ease of manufacture, consistency, etc. As a lock builder I welcome this change! But, costs go up, or profit goes down as compared to a cast lock.
Hybrids are a nice "middle of the road" compromise in manufacturing. The most complex parts (shape wise) are the hammer/cock and the frizzen. Depending on the lock, the top jaw and the lock plate (round faced and/or integral pan) can also be complicated from a CNC perspective. A lot of money can be saved by casting these parts. In order to CNC these parts without the cost going through the roof, requires a 5 axis machine (most machines being 3 axis). 5 axis machines are still relatively expensive as compared to 3 axis, and generating the code to run the machines is also much more intensive, fixturing parts is different along with many other considerations.
So as an example of a hybrid, take Jim Kibler's new offering. He lists the hammer, frizzen and top jaw as being cast. (I am fairly certain that Jim K's lock plate is cast as well, and the internal surfaces, screw holes, etc are CNC'd and/or surface ground. maybe Jim K will confirm -- UPDATE** I WAS WRONG! Lol) This makes perfect sense for a hybrid, and is the best of both worlds from a manufacturing standpoint. It similar to the direction which Chambers locks have been moving. Casting the complex parts and machining the rest is a big step up and I think we'll see more and more locks produced in this fashion. As well as other lock manufacturers moving in this direction over the next years.
So that takes us to fully CNC'd locks. The only one I am currently aware of is Chris Laubach's offering. (if anyone knows of another please let me/us know) This is far and away the most expensive option to produce for all of the previously mentioned reasons. I did have a chance to handle Chris' offering at Dixon's this year and it is impressive. As a cnc machinist, machining nerd and lock builder/enthusiast I was looking forward to seeing the quality of the 5 axis machining on the (complex) hammer, top jaw and frizzen. It did not disappoint. But we all know that type of machining and quality costs more money. I think we'll also see more fully CNC'd locks come on line over the next years, but price wise they won't be for everyone.
A few other notes/thoughts:
-springs: I haven't even broached the topic of springs. But they can be and CNC'd. That is a whole other can of worms. Cast, milled or forged they all have their different personalities, but the topic here was CNC parts so I'll leave that one alone.
-Left Handed Locks: One other advantage to fully CNC'd locks is the relative ease (as compared to cast) of converting your code to make left handed parts. It is a simple matter to "mirror" your CAD drawings and generate the code necessary for manufacture. So that is a plus in the CNC column that the Hybrid and Cast locks don't have.
-Materials, Tooling and Skill: Not all CNC parts are equal. Just like any other endeavor, metals (materials), the skill of the machinist, appropriate and well maintained tooling, etc. all play a part.
Boy, that was a rant...... I'd better go to the shop and make some money!
Best,
Chris E.