Procedure needed to re-set a Sargent Greenleaf Combination lock

[Mallard77]

Thanks for the reply. It sure looks decent as I would have a hard time getting it to open without the combination. If the knob was twisted off, it would allow access to the inside of the disks but how would one know how to align them? I guess that may be too much information to put on the forum.

So can this lock be upgraded? I am an engineer and machinist so I can handle most issues regarding a modification.

[Halflock]

In short, yes it can be upgraded. Now it is the question of what level of lock you want. There are several levels to think on. Group 2 is a standard lock with 3 wheels. Group 2M has some resistance to manipulation. Group 1 is better than group 2 and has 4 wheels. Group 1R is resistant to manipulation and some high tech attack and is mostly used by governments. Then you have electronic locks for ease of use as well. They will not last as long as the mechanical locks but they are much easier to use. If you do chose an electronic lock don’t place the lock over the hole that you put the cable thru as this is a retrofit. Also use a “Hard plate” mounting plate that will help protect in drill attacks. All these can be purchased thru a good security dealer. Here are some links to some locks that you can get.

Sargent and Greenleaf- Mechanical Combination lock
Sargent and Greenleaf- Electronic Safe Locks-Biometric keypad, high security lock
Safe Locks: Kaba Mas -
Safe Locks: Kaba Mas -

[wylk]

So can this lock be upgraded? I am an engineer and machinist so I can handle most issues regarding a modification.

This would be an interesting upgrade because the existing lock does not have a standard footprint, and because the boltwork of the door directly interacts with the lock's wheels. One of the first issues would be to mount a standard lock which might either require drilling/tapping new holes on the inside of the door, or possibly using an adapter plate if the extra thickness wouldn't be a problem (I vaguely remember seeing adapter plates for sale but I have no idea where; Lockmasters? Time Masters?). A "hardplate" here would add more resistance to drilling attacks. This assumes you would re-use the existing spindle hole. Note the door is probably filled with concrete or plaster, so a lock with a spindle tube would be desirable. As for the mounting holes there is a template on the last page of the S&G brochure at http://www.sargentandgreenleaf.com/p...500_ins_op.pdf. You might also need to drill new holes on the front for a newer dial ring (if you don't re-use the old one) but hopefully the new ring would cover up the old holes (dimensions are, IIRC, in the S&G catalog). Given that the safe is probably not terribly strong (see http://www.safeman.org.uk for examples of how burglars used to break into older safes), even the lower-end S&G locks (with spindle tube) would seem adequate although I'm rather fond of the 8500 series just because the mechanism is so ingenious (but you would not be able to re-use the old dial). And using an S&G lock, you might be able to re-use the existing dial and maintain the original appearance (current S&G spindles use 5/16-40 threads, vault spindles and the 8400 series use 3/8-30), also check the spline key dimensions in this case.

The next big issue would be how to adapt the existing boltwork to a new lock, probably this is a much bigger issue. Preferably if somebody tries to open the safe (without unlocking the lock) by twisting the handle, there should be no pressure on the end of the lock bolt. The boltwork of some safes/vaults use a twin "pincer" sort of mechanism that puts pressure on both sides of the bolt, but for a small safe another solution is for the boltwork to put pressure on one side, with a small welded bracket on the other side. Or just ignore idealism and do what is easiest as long as hard twisting doesn't break something that allows easy access.

I hope that helps without being discouraging!

P.S. your existing lock is probably in the 1927 catalog, page 38, the 6750 (the model number was later recycled for a completely different S&G product, the short-lived "Scrambler" lock).

[wylk]

An example of moderately-good boltwork is in US patent 4,520,736, figure 9. It is lacking the welded-bracket brace I described, which would go just to the left of "80" if included at all.

[Mallard77]

Thanks for the replies and the research. It looks like if I ever need to keep any considerable amount of valuables in my safe, I probably need another one! How does one go about determining if a safe is "safe"? Im starting to learn a bit from this forum and will keep local searching locally.

[Halflock]

AMSEC Safes U.L. Burglary Rating Classifications Explained
U.L. Fire Resistive Rating Classification Explained
Mercury Fire Ratings
Here is but one safe company and the ratings.
They make a good BF rate.
AMSEC Safes Commercial Security Safe
AMSEC Safes U.L. Listed Fire Rated Burglary Safes

There are other safe companies out there. The ratings are a US listing. This changes as you go to other countries.

[Halflock]

If you want a truly hard safe find a canonball safe. They are HEAVY and not cheap to move but are a REAL pain in the rear to get into if you are not tooled to do so. They have not been made in over 30-50 years at least.... I wonder when they did stop making those... anyone?

[Doug MacQueen]

From what I can tell the Great Depression brought an end to the cannonball era and for that matter many safe companies. Then the concern was more about armed robbery, aka Bonnie and Clyde.