Antique locks: were they supplied drilled for lockbolts?

[Acer Saccharum]

If I were to buy an import lock, say, back in 1780, would it come all casehardened? I assume so.

If so, would it be already drilled and tapped for the lock bolts? This might explain why some antique guns have locks (and sideplates) at wonky angles.

As an alternative, you might be able to get thru the case if you anneal the plate a little.

Anyone have knowledge of this?

Thanks,

Tom

[D. Taylor Sapergia]

Tom, Hans Muller sent me a great flint lock in unused condition.  I believe it is still soft (unhardened, and has no retaining holes.  I'll check to see if the frizzen is hardened.

[James Rogers]

 Mr. Brumfield from an earlier thread......

1. Some original locks, especially the cheaper imported so called "trade locks," had the internals cased but the plates were left soft.
2. Better locks appear to have had the plates hardened and those had the holes drilled and tapped first. One document discovered by Harold Gill when he was researching his book on colonial Virginia gunsmiths seemed to indicate that the lock bolts were included with the lock

[Acer Saccharum]

Then it would be the 'smith's job to caseharden....just like today! Actually, the cast steel plates in today's locks are much harder than the wrought iron of old locks. Most builders today don't bother to caseharden their locks.

Thanks, James, for your search.

[James Rogers]

Not much of a search because I like to keep posts that are of interest to me. Problem is that I remember some documentation to the effect of lock nails provided with import locks but that search so far has not proved successful due to a pc crash and replacement.  Will advise when I find it.

[T*O*F]

One document discovered by Harold Gill when he was researching his book on colonial Virginia gunsmiths seemed to indicate that the lock bolts were included with the lock

Wouldn't they have to be included?  Threads were not yet standardized and import locks could be sent to any country, not just here.

[hammer]

But then if the lock nails were included and threaded then that would predetermine the width of the stock at that point, wouldn't it?

Peter.

[Jim Kibler]

Lock nail could have easily been supplied slightly long and cut to size.  Doubtful they were often carburized.  If so, they could have been ground off.

[JCKelly]

My one experience here was when I was even dumber than now, and re-converted a plain southern long rifle to flint. Went to drill a hole for something, maybe new pan, anyway the drill skidded. That imported English lockplate had been hardened. More specifically, it didn't soften much when I tempered it with a torch. This means that it had a fair amount of nitrogen in the case, not just carbon (pardon the metallurgical lecture). A nitride, well here really carbo-nitrided, case is extremely wear resistant and does not soften at normal tempering temperatures.

To get significant nitrogen in the case, one pack hardenes in barely charred leather, perhaps lightly charred hooves or horn as well.

Hmmm - this still does not prove who hardened that plate, the English lock maker or the American rifle builder.  Oh, well.

[Gaeckle]

Then it would be the 'smith's job to caseharden....just like today! Actually, the cast steel plates in today's locks are much harder than the wrought iron of old locks. Most builders today don't bother to caseharden their locks.

Thanks, James, for your search.

Would there be any need to caseharden todays locks?

[rich pierce]

No need but a benefit.  Can reduce friction that develops with wear.

[LRB]

  I'm saying up front that I don't know, but according to Jerry Huddleston, all exported/imported locks from England/Europe were case hardened by order of the guilds, or they could not be sold. The guilds were very powerful during the 18th c., so I would suspect that he is correct. Would it be possible that some were exported as unassembled parts? Much as a lock kit today?

[Jim Kibler]

When you look at the quality of some of the 19th century Birmingham export locks, it doesn't seem the guilds had much influence at all.  Basically it was a manufacturing process and the quality was sometimes pretty bad.  Was case hardening done at the bare minimum if not at all in some cases?  I'm sure, based on the other characteristics and obvious concern for production time and cost.

[Acer Saccharum]

Here's a Germanic import lock. Used on a Rev-war period gun. Killer quality. It would not have lasted were it not hardened. Note that it's 'screwless', no screws from sear or sear spring show on the front. End of frizzen spring screw is engraved. Pretty neat.

[kutter]

My one experience here was when I was even dumber than now, and re-converted a plain southern long rifle to flint. Went to drill a hole for something, maybe new pan, anyway the drill skidded. That imported English lockplate had been hardened. More specifically, it didn't soften much when I tempered it with a torch. This means that it had a fair amount of nitrogen in the case, not just carbon (pardon the metallurgical lecture). A nitride, well here really carbo-nitrided, case is extremely wear resistant and does not soften at normal tempering temperatures.

To get significant nitrogen in the case, one pack hardenes in barely charred leather, perhaps lightly charred hooves or horn as well.

Hmmm - this still does not prove who hardened that plate, the English lock maker or the American rifle builder.  Oh, well.

Thanks for the info on the nitrogen in the hardening.

Maybe the part was cyanide hardened?
I've worked with cyanide case hardened items a lot and they do not always anneal by the torch method as a bone/charcoal case hardened part will.
They often emerge from the annealing process seemingly as hard or nearly so as when you start. A second or third trip under the torch will usually do it.
Annealing them in a covered bed of charcoal or ashes and left to cool will do it in one trip. Maybe something to do w/the torch gases?,,don't know.
But they're never quite the same (as soft) to cut as the bone/charcoal parts annealed w/a torch flame.
Not a expert of any sort,,no explanation for the difference,just an observation from personal experience.

[Jim Kibler]

That is a great lock, Tom.  Certainly not too many corners cut on this one.  I'm envious every time you post pictures.

Jim

[keweenaw]

There is case hardening and then there is case hardening.  A part can be case hardened and have only a minutely thin case, like .0005-.001 thick.  Since that little case will crack with a center punch mark, it's no big deal to drill and tap.  On the other hand the case can be very thick and drilling and tapping without annealing is about impossible with steel bits.  How much case is a function of the parent material and the time and temperature in the pack. To slick up a lock and provide a wear surface only a thin case is needed but this is all best done after all drilling and tapping. There is a guy on the Marlin Collector's board that gets beautiful case colors but he's quenching from 1100 degrees so he's not getting any hardness at all.  Even his soak at 1325 would be putting an almost imperceptible amount of carbon into the surface of the work.  What he's doing is really scary since he's taking an originally case hardened receiver and turning it into an annealed receiver. 

Tom

[RAT]

Beyond the question of lock bolt holes...

Engraving would also have to be done before case hardening. Some locks were certainly supplied with engraving already done. This would have been true during the 18th and 19th century (see Gary Brumfield's website). I've always thought that locks were case hardened by the manufacturer, but now I'm not so sure. I'm out west and don't have access to a lot of originals. Can someone who's seen a fair number of original locks comment about any remaining finish?