"Bill" wrote in message
...
On 6/22/2012 8:04 PM, LeeAtWork wrote:
I've been a locksmith for 40 years now, and I usually work out my own
solutions, 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
different 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. Contrary to myth, nothing in even a high-security lock needs to
be accurate to more 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 piece called a sidebar. You can easily find a
picture thanks to someone misspelling the caption on a photo of one. Use
Google Images to search for "heres's finger pin" and it will be one of
the first images in the results.

Anyway, 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 do 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 used 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 to get dull, I need to brush off the burrs on
each pin by holding it in a pair 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 kit, since a bad pin in a lock cylinder
will waste a lot more time than testing 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 worker!)

Questions:
Is there a machine that could fit on my workbench that is designed to
repeatedly make precise cuts on tiny pieces of metal like this?

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
moves? 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
nickel silver? I saw a pneumatic pencil grinder that spins at 100,000
RPM, which might make cleaner cuts faster, but might have some other
problem I don't know about. The cuts are so small and take so little
time, that heat may 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
speed 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 mention of brass alloys. Is there a kind of milling cutter that
is better for brass?

Thank you for any help you can provide.
Lee


if you could make an accurate drawing of what you want you could probably
get them made for a surprisingly cheap cost


Would probably be a perfect job for someone with a swiss turning center, I
could probably knock them from 12 ft bars of raw bar stock in a minute or
two per part but I've already got more work than I feel like messing with as
it is.

Anyways, pretty sure you're talking about the "notches" in this part:

http://bp3.blogger.com/_Vn-QxkKF9KQ/...0/DSCF5572.JPG

If so, you might want to buy yourself the smallest, cheapest
mini-metal-lathe that you can find and remove the headstock and tailstock
from it altogether, and then mount a pair of dremel-type tools in their
place, on vee blocks, facing towards each other, similar to what is commonly
known as a "duplex milling machine"

Then make a jig to hold your part in the toolpost, moving the part left to
cut one notch then to the right to cut the other...simple carriage stops or
even a pair of c-clamps could be used to control depth of cut....

Or, a similar arrangement could be setup on an say...an old hardinge second
op lathe, in which case you would use a lever type production slide instead.

Good luck have fun glad it's not my problem.