Lock plate thickness

[Camerl2009]

Hi all I have a copy of the book recreating the double barrel muzzleloading shotgun. In the lock building section it talks of using 3/32(.093) to 7/64(.109) thickness steel for the lock plates.

Would that be on the thin side of things?

[Longknife]

  I believe that is about right for a small late English flintlock, but I would prefer the thicker steel, say .109.,,,LK

[Bob Roller]

Hi all I have a copy of the book recreating the double barrel muzzleloading shotgun. In the lock building section it talks of using 3/32(.093) to 7/64(.109) thickness steel for the lock plates.

Would that be on the thin side of things?

I would NOT use a .109 plate if I were MAKING the plate but I don't recall ever checking a cast plate for flint or percussion locks.
A lot of my caplock plates were milled by me and I thought a .125 FINISHED thickness was minimum and preferred .130+.
Before 1967* all my caplock plates were made from .125 Cold Finished 1018 with the bolster/shoulder riveted in a way that I hoped
would not interfere with a cross bolt.A 3/32" lock plate might work but the screws would have to be IMHO very fine and special thread taps and dies would be needed.There is a big difference in MAKING a lock from preselected materials and a kit.Either will get the job done but I always wanted to have at least an idea about what I was using and the cast parts were troublesome and with minimum or no quality control so my choices are 1018 for lock plates and bridles,1144 for tumblers,01 flat ground or gauge stock for sears and flys and 1075 for main and sear springs.I did insist on being paid for the time it took to make these odd items and for reviving old skills required and my ideas about quality control and what the buyer deserves are well known.Locks and triggers were about 30% of the work in my shop and the rest was
automobiles in the form of bronze bearings for transmissions and one of a kind bolts for some pre WW 1 cars and motor cycles and ONE door latch for a Cessna 195 plane to hold the door open when on the ground.It was my favorite old bird if you see one at an airport with 3435V it is the one.It also said "Yesterdays Wings" as part of the paint scheme.The last automobile job was a complete set of screws and nuts for a Canadian who had a Duesenberg and I made all those including shacle bolts and bushings.
*1967 was the year I bought a tool room milling machine,a new Clausing 8520 and I still use it now on a once in a while basis.
Bob Roller   

[Camerl2009]

I really don’t see any reason why it couldn’t be bumped up to 1/8  I have lots of bar stock around that thick.

 My plan for the locks was to use what I have on hand mostly for materials I will need some drill rod ect if I follow these plans.
for springs I was looking at a set of old leaf springs I have the lock plate and bolster/pan I should have something that will work in the pile.

No real mill work involved according to the book it’s mainly hacksaw files and torches for bending an heat treating.

[P.W.Berkuta]

I guess if you are making a lock from scratch you can make it from what material you want. You just need it to work in the end - then there's mating it up to the rest of the parts on the gun.

[rich pierce]

I’ve a large early Germanic lock that is close to 3/16” thick. And an early round faced English lock that is ridiculously thin. It varies a lot. Military locks tend to be more sturdy.

[Bob Roller]

I would not even think of leaf springs from cars and annealed 1075 is available from McMaster-Carr,I used 1/8" with a 100% success rate.
There are a variety of easy to get materials available.The 1144 I mentioned is also called "Stressproof".It machines like leaded steels like 12L14 and hardens in oil.!2L14 makes fine screws bit little else and is available in about ant size/diameter needed.There was an old gunsmith here in Huntington WVa that got flat section coiled springs that were used on older cars for hood and trunk lid supports and then
he'd anneal them in a coal burning stove and straighten them out.It was a gamble to make gun springs from this material and I showed him a spring I had just made for a lock that had just cooled off enough to handle and the installed it in the lock and he was amazed at the strength and flexibility he saw.I gave him a strip of 1075 and after that he had no more trouble with springs.He had the ability but never
was aware of the materials available on the open market.
Bob Roller

[Camerl2009]

I was looking at 1095 for springs when I first started reading this book but I guess 1075 would be better.

The other book I have(on lock making)talks about using model A Ford springs. the springs I have came from an old pop up camper that I reused the axle out of. there is also a dodge caravan spring but that broke so I don’t really trust it for anything and soon there will be a pair from a 04 Chevy pickup.

Springs are close to 1095 or 5160 so I have been told over the years I wouldn’t know about the hood list springs but my 90 Chevy still has those and I have seen some newer cars and trucks that have that system.

[Camerl2009]

Looks like I can get more then enough 1075 for about $8 Canadian.

[Longknife]

I  just measured a few lock plates I have,:
 Dixie lock .109
L&R Bailes .112
 L R D Egg  .118
L R Tulle     .149
L R Jaeger  .172

[Camerl2009]

Other steel I will have to grab plans call for drill rod of a few diameters.

Most of the steel I have is mild have about 2 ton of random lengths of tubing bar stock and some plate all drops from a local company that I got for less than scrap price.

[Clint]

Springs from a model A are made of plain carbon steel as are many things made before ww 2, hay rakes, harrow tines etc. After the war "every thing" had to be made from alloy steel and the heat range is a pita. 1095 is a plain carbon steel but it is very fussy about heat, If it overheated by just a little, the grains distort and cracking becomes a problem. Acetylene torches are notorious for over heating and you should use the biggest, softest flame possible. Look up PHASE CHART for steel on the web. The chart is a graph which illustrates the phase changes in relation to temperatures and carbon content. It will tell you how much heat to use for hardening. having said all that,1075 will make good springs and if you have the courage, can be water hardened. I make all of my sears, tumblers and bridles from hot rolled mild steel and carbon pack them to harden. The out board stuff is made of wrought iron and pack hardened.