Unfortunately, changing the depths from factory(OEM) depths will not change
the potential for 'Bumping' except for one particular case..... Most 'Bump'
keys are being cut using the lowest possible factory(OEM) depth.... i.e.
Schlage #9 .300 bottom pin. In my shop we have cut 'Bump' keys to the lowest
depth and then used a Pippen file lower them several strokes or about .005.
This allows for a #9 pin(Schlage) to still be able to develope the inertia
it takes to srike the top pin so that it can rise above the shear line and
catch. An exact depth of .300 would mean the slight rise would put the
bottom pin accross the shear line. Now what happens when someone(a thinking
locksmith) cuts a Schlage key with a #10(.185) cut and uses a #10 bottom
pin(.315) in his new combination choice??? The 'Bumpkey' cut between .300
and .305 is now rising accross the shear line as soon as the bumpkey is
inserted. 'Bumping' foiled!
I'm not testing every manufacture and assuring everyone that a lower cut is
possible, because that will be solely dependant on the shape of the
broaching. Radical angles can be the potential hinderance from this
procedure............ but, here in Australia, where Lockwood has remained
supreme for so many years, the C4 keyway is practically the standard here.
I know for a fact that the C4 keyway will allow for a #10 cut(refered to as
an 'A' cut by Instacode), and a #10 top bottom pin is totally available. We
have tried the regular 'Bumpkey' and it DOES NOT OPEN the lock.
Don't forget, in your hurry to try this, to remember to use the smaller
top-pin in combination with this larger bottom-pin. If you get cluey enough
to remember your MAX values, and use this larger bottom-pin next to a much
smaller one, you will find that normal picking becomes quite difficult.
Everything is possible when considering methods of keyless entry, but I'm
just offering a cheap and easy way to thwart the majority of attempts. The
absolute answer lies in locks that don't work with the standards we have
relied upon for years and years. The future will be interesting to say the
- posted 14 years ago