Building a robot to discover the combo of this old Yale safe...

[bcrimmins]

Greetings! I recently acquired this old safe that hasn't been opened in decades and doesn't have a combination.



I'm building an computerized/electronic/mechanical contraption (call it a 'robot') to automatically try every possible combination until it finds the right one. There are theoretically 1,000,000 possible combinations, so it could take a week or two for it to crack it. Given that long time investment, I want to be sure I'm attempting to dial the correct number of digits, in the right directions and with the correct pattern (i.e., four turns, three turns, two turns, etc.)

If anyone recognizes this locking mechanism and knows for certain what the dialing parameters, I would be grateful for your help in getting this right the first time.

Thanks in advance!

Bob

[oldlock]

You may have a slightly more complex problem as that lock could be a direct entry lock. Easy to test. Turn the dial, note the torque required. Now crank the handle hard one way and then the other and see if the dial gets harder to turn.

If thats the case then you will need to two stage machine - one that turns the dial and another that turns the handle ...

Probably much cheaper to take it to a locksmith .....

[bcrimmins]

oldlock, that's a great insight regarding testing the mechanism! I will definitely do that today. I was actually hoping that turning the handle turn would be required because I think I know how to build a solution to do that. (Some of the other possibilities we're going to be even harder to solve for.) But I didn't know how to test for that. I'm grateful for your advice to determine that.

You're absolutely right about the cost and complexity of building a robot instead of just paying $200 to have it opened by a pro; the rational thing to do would be to just pay the money and move on. But what fun is there in that?! Honestly, I'm just a maker in search of something to make. The fact that it's a hard problem to solve and actually might not even work is like telling me "careful... there's frosting on that piece of cake."

Cheers,

Bob

You may have a slightly more complex problem as that lock could be a direct entry lock. Easy to test. Turn the dial, note the torque required. Now crank the handle hard one way and then the other and see if the dial gets harder to turn.

If thats the case then you will need to two stage machine - one that turns the dial and another that turns the handle ...

Probably much cheaper to take it to a locksmith .....

[Dean Nickel]

So your after the solution of the problem not the solution. That is cool too.

[bcrimmins]

Yes, Dean, that's it. I know I can build a robot to perform the actions necessary to brute-force solve for the combination... I just need to what those actions are. I have a safe with a lost combination now, but now I want to build this contraption badly enough that even if I didn't have one I would go and buy one just to try it! :)

To clarify, here are the specific questions I have:

1) is this safe likely to have a three-number or four-number combination?
2) should the first number be dialed to the right or to the left?
3) what are the likely steps, i.e., "dial to the first number four times, dial to the second number three times, dial to the third number two times, dial to fourth number once, then try to turn the handle"?

If I have a solid understanding of these things then I'm confident I can't get it done.

Thanks,

Bob

[Doug MacQueen]

If you email me at macslocks@gmail.com and are not in a hurry, I can help you with this. The robot you want to make has been around for quite a long time. There are a few things to consider. For example if the wheels exhibit wheel walk, the robot will fail if it is dialing fast enough to cause this. Wheel walk is when the wheel keeps rolling after the dial is stopped. Not a common problem on old safes but sometimes happens. Doug

[bcrimmins]

Thanks, I will email you now.

Bob

If you email me at macslocks@gmail.com and are not in a hurry, I can help you with this. The robot you want to make has been around for quite a long time. There are a few things to consider. For example if the wheels exhibit wheel walk, the robot will fail if it is dialing fast enough to cause this. Wheel walk is when the wheel keeps rolling after the dial is stopped. Not a common problem on old safes but sometimes happens. Doug

[Brian Smith]

Hey Bob,


Once you get it made and set up, keep this in the plan; Locks are meant to be opened by the known combination, maybe ten times a day for its lifetime. When your machine starts running combiations, non-stop all day long it causes friction not compensated for in the design. Even a human manipulator cuts down the revolutions by using knowledge and senses. Read up on lock manipulation before you write your program. Failing that, make a lube injector to keep it free wheeling.

[bcrimmins]

Thanks, Brian. That's a great point. With hundreds of thousands of likely potential combination, it's definitely going to get a work. I like the idea of a lube injector. I'll noodle on that. The story from the guy I bought the safe from was that it hasn't been opened in 30 years. At 10 open/close cycles/day, that's 3,650 per year... and 30 years is 109,500. Maybe that'll buy me a little luck... and some time.

Question for you: would the speed of turning the dial affect wear? If I slow it down it will take longer to get there... but if it causes less wear then I would do that. The primary objective of the project is to crack combination, but if there's a way to preserve the the mechanism somewhat then that would be preferable.

[Doug MacQueen]

Just to be clear guys, building an auto dialer robot is considerably easier and less complex than building an auto manipulator. Yes, the auto manipulator will be easier on the lock, but not so much on your head. Either way, a complete study of the particular lock you are working with is pretty much necessary, prior to building it. An important question to ask is, does the lock come to stop as the dial is turned to the last number. Most do but not all. For example the Diebold dial discussed in the other post does not come to a stop on it's own.