Drilling a casehardened lockplate w/ a drill press or Dewalt drill w. a carbide bit may be possible now but it sure is not w/ a hand drill
Really ?? You mean they didn’t have diamond tipped titanium drill bits back then .
Surly the local “ La old Home Depot” or “ Francqua True Valuable” had at least cheep B&D junk
But truly Im jesting .
Maybe they did pre drill and tap . Personally I don’t know . But it would seem a foolish thing to do . Not only would it raise the cost of the product . It would also require a reasonable standardization of thread counts , thread pitches. As well as a fixed bolt size .. Not to mention required locations for an unknown end use .
So were gunsmiths making their own bolts and screw or where they also buying those .
It would seem to me that it would be far simpler to drill and tap for ones own threads and sizes .
I also think today we think of hardened steels which can be hardened to a much higher degree because we have the available tooling
But why would one in the 18th century , harden a material to the point it exceeded the ability of existing tooling of that time .
Myself though I would think that surly somewhere there has been found a ship wreck that carried a shipment of locks “other then military “
Im thinking there in would lay the answer .
How much penetration do you get from case hardening? If it's not that deep, maybe a center punch might get you thru the hardened part and the hand drill could penetrate from there on? Probably dumb questions, sorry.
It depends on how its done and what material is used . Its entirely possible to through harden some steels .
Imparting more carbon into a mild steel during a case hardening process doesn’t harden to any real depth . The quality has to be their first
Thickness of the part also plays a part .
If we look at 18th century locks and then compare their lock plate thickness to say a late 19th century Greener lock plate . , we find that many times that later lock plate is much thinner in its cross section .
I can tell you that I have re drilled and tapped some Greener and Parker locks that were so soft that one could use a cheep soft drill .
Now that’s not to say there isn’t places on the plate that are not very hard . Tumbler holes for one .
or say the locking lip on the forward edge a Crescent box lock .
Very Hard area . But at the same time farther back on the lock plate can many times be so soft that it seems one could just about use a punch and drive through the lock plate