Help: Opening Procedure for old Yale safe lock

[WeirdoC]

First post. I'm a hobbyist locksmith, but I've never gotten into learning about safes, so I'm reaching out with this issue.

I work for a small public transit authority. We have an old safe in our building that no one knows how to open. We don't have a combination, but someone very clearly marked several of the numbers on the dial with markers at some point years ago. There are three numbers with bright paint marker lines, and one more with a harder-to-see Sharpie mark. I have been trying to brute force it with the full permutation of these numbers, but I have no idea if I'm actually turning the dial in the correct way. I am hoping someone can positively identify the lock type and the proper turning technique so I can retry the combinations with some degree of confidence. I've found a few pictures of identical-looking lock dials online, but not anything that seemed to positively identify it or the proper turning method.

The lock is YALE branded, but I see no other identifying marks anywhere on the safe. The dial has a doorknob-like central protrusion, and the dial does not bind at all when the handle has tension applied to it. The distance from the center of the dial to the center of the handle's pivot is about 4-1/4".

[MartinHewitt]

Hi, This is a good description how to open a combination lock: https://www.youtube.com/watch?v=qEYjgOFKR1U
I think that your cabinet has a Yale OC-5, which has reversed dialing. So instead of starting with a counter clockwise/left turn, start with a clockwise/right turn.

[WeirdoC]

Thank you for the lock ID. I was able to find a PDF of the original OC5 instructions thanks to that, so I will retry the combination permutations with a lot more confidence that at least the turning sequence is correct for the lock.

[WeirdoC]

The safe has now been opened. We finally found an employee who had the original combination card in an old wallet. He said the last time he had personally opened the safe was like 8-10 years ago. The most recent date that appeared on anything inside the safe was 2012, so I'm assuming he even underestimated how long it's been.

There was a little bit of cash, but not much. Under $100 total. Lots of bus tokens, some license plates, and a bunch of car keys for mostly vehicles we no longer have.

The lock has a 4-digit combination , and the turning sequence ended up being LRLR, turning the handle after stopping on the last digit. Based on the instructions for the Yale OC5 I found online, it looks like this isn't that particular model after all. I'll try to pull the back off the door next week on my lunch break and get some pictures of the inside to share.

[MartinHewitt]

Great you have it open. That sounds like so called straight tail-piece lock.

[Squelchtone]

The safe has now been opened. We finally found an employee who had the original combination card in an old wallet. He said the last time he had personally opened the safe was like 8-10 years ago. The most recent date that appeared on anything inside the safe was 2012, so I'm assuming he even underestimated how long it's been.

There was a little bit of cash, but not much. Under $100 total. Lots of bus tokens, some license plates, and a bunch of car keys for mostly vehicles we no longer have.

The lock has a 4-digit combination , and the turning sequence ended up being LRLR, turning the handle after stopping on the last digit. Based on the instructions for the Yale OC5 I found online, it looks like this isn't that particular model after all. I'll try to pull the back off the door next week on my lunch break and get some pictures of the inside to share.

Does the dial stop dead on the last digit before you turn the door handle, or do you have to stop on it accurately and then turn the handle? This would determine if it is a 3 or 4 digit combination. if the dial stops dead before you turn the handle, that last number it stops on it typically not part of the actual combination, it is just part of the dialing sequence.

Glad you got it open, this post was fun to follow! It's amazing you found someone that still had the combination in their wallet, that's very rare in this racket.

Thank you for sharing your story with us,
Squelchtone

[WeirdoC]

It turns freely past the last digit. You actually have to stop on it and turn the handle for an open, so a true 4-digit combination lock.

[WeirdoC]

Correction: I was mistaken, and it does stop on the last digit. I had opened it once before and didn't feel the stop, but I just tested it again.

So, whatever model this is, the turning sequence is as follows:

• Turn LEFT, stopping when the FIRST # comes the FOURTH time.
• Turn RIGHT, stopping when the SECOND # comes the THIRD time.
• Turn LEFT, stopping when the THIRD # comes the SECOND time.
• Turn RIGHT slowly until the dial stops, then turn handle to open.

[MartinHewitt]

Then it could be a Yale Y-6.