On 2012-10-10, Doug Miller wrote:
Jon Elson wrote in
:

Ro Grrr wrote:


I'm getting a DIEBOLD FILE SAFE that is about 5 feet tall and 3 feet
wide, double doors. Its locked and there's no combination so I'm
probably giong to have to drill the door to get into the combination
lock.
Do you know if it is a 3-number combination or 5? If 3 numbers, I'd
just try them all, it is probably a lot faster than trying to drill
a good safe, even if you knew the exact spot.

I don't know much at all about safes... but I do know a little bit about math.

If there are (as has been suggested up-thread) 100 numbers on the dial, "try them all" is not
practical, as there will be either 100*99*98 = 970200 possible combinations (if a number
cannot be repeated) or 100^3 = 1 million (if it can). Assuming five seconds per try, with a
standard 40-hour work week, the OP could expect to finish trying them all by the end of June.

Five seconds per try is not practical. Four full turns (or
more) to the left, stop on first number. Go past the second number to
the right twice and stop on it the third time. Left again, past the
third number once and stop on it the second time, then go right to zero
(assuming normal dial position), turn the little turnbar in the center
of the knob, rotate right to hook and withdraw the bolt, and then
operate the lever to unlock the door/drawer.

You can't go very fast on these or the inner discs will
overshoot the numbers (and thus the proper stopping place) by inertia.
(This on the S&G locks, the Mosler are both somewhat more tolerant of
that, and have a low inertia dial, so you can't spin it freely -- it
takes effort.)

On either lock, you want a thumb ready to press on the OD of the
dial to slow it to the target and then hold it there while you shift
your grip.

My own feeling is that it would be more like a minimum of 30
seconds, and likely 45 per try, which makes the time required grow
rather rapidly. :-)

If there are only 45 numbers on the dial instead of 100, he might finish by the end of this
month.

Multiply by at least six for the longer time to work the
combination, so you are up to a half working year with the smaller
number of combinations.

BTW -- the same number can be used for the first and last entry,
but should not be used for two immediately adjacent entries. And
really, you want something like a separation of two or three. And the
last entry should not be zero, because there is a permanent zero
following that.

Enjoy,
DoN.

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