mm wrote:
Can one open a combination lock without knowing the combination?

I'm helping to clear out a building which is about to be torn down,
and in the office is a sheet metal cabinet, with a door on the left
side and two shelves inside, and on the right side is a larger door
with a safe-style lock on it, a single dial, a black plastic wheel
with numbers on it.

I saw a device designed by an engineering student used to open a combination
padlock. Its major parts were a small logic board, a servo, and a solenoid.
After attaching the servo to the dial - and a little alignment - the sucker
diligently went through every possible combination!

Always worked.