Years ago, I made locks including the springs and screws, with nothing more than files, hacksaw, machinist's vise, propane torch, and a bench grinder. I used a portable electric drill clamped in my vise for a lathe to make the screws, and a tap and die set from a hardware store I bought for $10 (1971). Even then, I was using Kasenit to case harden the screws. You also need a set of Vernier's calipers, or a micrometer (better). They turned out well and are still functioning just fine, So it can be done, with the appropriate level of determination.
From this primitive start, I now have a drill press, small mill and a good lathe and a 6 x 48 belt grinder, but most of the work is done by hand with saw and files. Certainly, from cast parts, small hand tools and polishing abrasives is all you need. ...plus the desire and patience to see it through with thoughtfulness and care.
Robert Roller is arguably the king of making locks in a metal shop. Perhaps he will chip in.
No king,no way not even close. Lock making is a labor intensive job and anyone that can make a lock
using less equipment than I have is a good machinist/mechanic.I have one heavy drill press,a tool room milling
machine,four lathes one of which is modified for screw making,two metal cutting bandsaws,one vertical and one
horizontal. A very wide assortment of files from tiny to big.Two bench grinders,one is as bought and the other
modified to use as a polisher and grinder.Also a wide variety of precision measuring tools such as a real Vernier,
two dial calipers and several sets of micrometers. There is also a pre WW2 Mauser combination Vernier caliper
and height gauge calibrated in decimal readings.I use it occasionally with adjustable parallels for laying out odd,
non muzzle loader related jobs.ALL of this is old American equipment except the Mauser gauge.
I made my first lock in Bill Large's shop in 1953,mostly with hacksaw and files.He helped me with the springs
and the screws were common hardware store items.It worked and I was happy with it.
In the last 63 years I have been in and out of lock making but have settled on material I KNOW works for me.
12L14 for screws,1075 for main and sear springs and 1144 Stress proof for tumblers.Bridles and trigger bars
are 1018 and triggers are 1018 case hardened or made from 0-1 if I am really energetic.Pins are drill rod.
I can't do an article on making a lock but it is a skill that requires time and lots of it.Cut and try,measure and cut
and try to visualize what the job will look like when it's done.DON'T worry if it's not perfect. NONE of them are no matter what
length of experience you have.Locks are part machinist,bench and artist skills and it takes time to bring all that together
into an operational ensemble that is useable and reliable.
Don't quit if the first lock is not right.My experience tells me it might not be all you want it to be but don't stop trying.
I might be one of the last to bench build a lock in our time for customers.I am not seeking new new work and am
tired. I have a number of pending orders that I may or may not finish.None are paid for and it has been my policy
for years to NOT take advance payment or promise delivery dates.
Bob Roller