Group 2 Lock Question

[DB in Oregon]

Several months ago I purchased a safe that was probably made in the late 90's based on the serial number. It has an S&G 3 wheel lock in it. At that point I knew nothing about these locks. I started reading various S&G documents and eventually realized that my lock's 3rd number was in the forbidden zone for a dial splined at 41. I purchased a change key and successfully assigned a new combination.

A couple of months later another safe appeared on Craigslist with a combination lock at a ridiculously low price so I bought it as well. It is a much lighter construction but it serves it's purchase. I wanted both safes to have the same combination so I changed it to the same combination as the first safe. The dial is splined at 50. The 3rd number is clear of the forbidden zone.

The lock on the second safe has "International 2000" cast into the backplate. It came with a change key that is identical to the U8 key for the S&G that I had purchased.

I was thinking about replacing the International 2000 lock and purchased a S&G R6700 series lock on Ebay that someone had removed from a safe when they upgraded to an electronic lock. I was able to align the wheels so that I could change the combination without knowing the existing combination. It works flawlessly. It is also splined at 41.

Here's my question: Both of the locks splined at 41 will allow the bolt to be retracted when the correct combination has been entered. Both of them will allow the bolt to be extended and retracted again as long as the dial is not rotated past the 3rd number thus moving the 3rd wheel. After retracting the bolt on "International 2000" as soon as the nose on the lever leaves the notch when extending the bolt the lever nose will not drop back into the notch in the cam like the other locks. It appears that the wheels have moved a small amount but sufficient to prevent the fence from dropping into the gates again.

Is this a bug or a feature? Is it related to this lock being splined at 50?

Also, the internal parts of the International 2000 look identical to my 2 other S&G locks. Are these locks made by S&G?

Thanks in advance for your help.

Dan
Corvallis, OR

[Squelchtone]

Moving this from This Old Lock (meant for pin tumbler door locks) to This Old Safe (safes and safe locks)

[MartinHewitt]

Hi Dan, locks being not reunlockable are very common. When you extend the lock bolt there is an upward force on the lever because of the ramp in the drive cam gate. So the fence of the lever exits the wheels' gates as early as possible. Often, especially when there is a ball detent or similar mechanism inside the lock, the lock bolt moves a bit further. Then the edge of the fence will sit on the fence of the gates and doesn't drop down.

Regarding the forbidden zone: When the lever has dropped it interacts with the last wheel (the one next to the drive cam) by the fence in the gate and if in the last number is in the forbidden zone simultaneously also via the drive cam and its pin and the fly of the wheel. If this is in the middle of the forbidden zone you won't be able to unlock the lock after you changed the combo or you won't be able to lock it. So you are warned. Dangerous is when the combo is on the edge between good and bad and slightly on the bad side. Then there is still a force on the pin and fly, but the lock works and you barely notice it. This can lead to a snapped fly and turning the dial won't turn the wheels anymore. You could check that during the bolt retraction and extension there is always at least a little play between drive cam and the next wheel.

[DB in Oregon]

Hi Martin,

Your explanation of the interaction between the lever nose and the drive cam describes the problem exactly.

After I posted my question I did a little experimenting with the lock last night. I found that if I placed a shim made from a piece of a credit card (.035") between the top of the lever and the inside of the case it delayed the lever nose from leaving the cam gate enough to rotate the wheelpack just enough for the fence to fall back in. So, the mystery is solved. At this point I'm going to leave it as it is. It's really not a problem. It just didn't make sense to me.

My first safe originally had a 3rd number of 90. According to S&G documentation the forbidden zone for a lock splined at 41 is from 90 to 99 and 0 to 10. The new combination doesn't violate any of the S&G rules or suggestions.

Thanks for your reply.

Dan
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