I've been a locksmith for 40 years now, and I usually work out my own solut= ions, but this time I could use some help figuring out a better one.
I need to modify several thousand "finger pins" so I can use keys from 2 di= fferent series in the same locks. The pins are made of a hard, high-nickel= brass called "nickel silver" about 1/8" diameter (actually 0.115") and are= roughly 0.33875" long, give or take 0.00025". (Okay, I'm kidding. Contrar= y to myth, nothing in even a high-security lock needs to be accurate to mor= e than 0.003".) They have a short hole in one end and a "finger" sticking = out of the side of the other end. There are a pair of cuts 1/16" wide and =
1/16" deep on each side leaving a bar that fits into a slot in another piec= e called a sidebar. You can easily find a picture thanks to someone misspe= lling the caption on a photo of one. Use Google Images to search for "here= s's finger pin" and it will be one of the first images in the results. =20Anyway, I need to make a second pair of the same kind of cuts in around 500= of each of 4 shapes of pins and am wondering if there is a better way to d= o it than what I've been doing.
Currently, I've modified a quick-release vice to hold 1 pin and mounted the= vice on a lazy Susan so I can get at both sides of the pin. I put the pin= in, and then use a Dremel flex-shaft tool spinning at 35,000 RPM with a 1/=
6" carbide 2-flute end milling cutter to make the cut on one side, spin the= vice and make the cut on the other side. I wear a double magnifier on my = head to see what I'm doing, and, well, my hands aren't as steady as they us= ed to be, so the cuts don't always end up as neat and clean as I mean them = to be. If the cutter is new, I don't have to deburr, but after it starts t= o get dull, I need to brush off the burrs on each pin by holding it in a pa= ir of tweezers against the wire wheel that I use for brushing off keys. I = take a few more seconds to test each pin before putting it in my pinning ki= t, since a bad pin in a lock cylinder will waste a lot more time than testi= ng it before the lock is closed up.I can modify and test 60 finger pins in two or three hours, and then I have= to stop and do something else. (I would not make a good assembly line wor= ker!)
Questions:=20 Is there a machine that could fit on my workbench that is designed to repea= tedly make precise cuts on tiny pieces of metal like this? =20
If not, is there a place to look for designs for jigs or tool holders so I = can mount the end of the flex shaft in a way that will limit how far it mov= es? I'd like to have something where I slip in a pin, swing the tool down = and up to quickly make the cut, and then slide out that pin and pop another= one in.
Is 35,000 RPM the best speed to use when making 1/16" cuts 1/16" deep in ni= ckel silver? I saw a pneumatic pencil grinder that spins at 100,000 RPM, w= hich might make cleaner cuts faster, but might have some other problem I do= n't know about. The cuts are so small and take so little time, that heat m= ay not matter, but I have no experience with such a tool.
Is there a formula or something to figure out what is the best working spee= d for a particular kind of metal and size of cut?
The carbide cutter manufacturer claims it is for cutting "Aluminum, Carbon = And Tool Steel, Cast Iron And 300 Or 400 Series Stainless Steel," but no me= ntion of brass alloys. Is there a kind of milling cutter that is better fo= r brass?
Thank you for any help you can provide. Lee