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Securety: Closing employees only, cant get back in.

I recently had a request from a pizza establisment to, "make it so my employees that close the store at night, can't get back in after they turn the lock to the lock position". I didn't think it was possible... Until I took the lock apart and saw the modification to the lock cylinder that had already been done. A co-worker years earlier, had cut .0020 grooves on ONE side of each chamber, starting from the top of the pin stack (grooves are the same width of a pin), around to the bottom of the split in the cylinder plug. (grooves are cut on the right side only, so the key would only turn to the left). Then put .0020 top pins in. So that the 'openers' key would turn to the RIGHT or LEFT. I was seriously amazed at the hack (Nice work).

Is this genious, or old school?

mac

Reply to
Mac
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Look at the thread from 2002

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Or
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Or serach google groups for 'alt.locksmithing: "lock+only" owner keys'

Daniel

Reply to
dbs__usenet

Thx dbs,

It's nice to come across something that makes you go, "that seems like it should have been obvious to me, and humbles you back to thinking again." Lock work is not an exact science.

mac

Reply to
Mac

I have been doing this kind of thing since the early 80's. I saw an asian import fire safe that had this kind of thing on there safe but they had it so one key would turn to the right only and one to the left only.

Reply to
Roger Shoaf

Both :-)

regards - Ralph

Reply to
Ralph A. Schmid, DK5RAS

Charles Courtney described such a lock in his book 'Unlocking Adventure'. It was used on a horse drawn 'paddy wagon' used to transport prisoners from Moscow to somewhere in Siberia. It was locked with one key in Moscow and unlocked with a different key kept at the destination.

Reply to
Peter

My understanding is this is for 360°-turn locks and that if the "master" key is rotated in the locking direction, say 90°, and returned BACK to the neutral position the top pin will contact the side of the bottom pin and prevent the plug from returning to the neutral position. Have I got the right picture? Wouldn't that be a problem if the master key is accidentally turned more than 360°?

Amazing the simple solutions to a problem people can come up with.

Bud--

Reply to
Bud

I've read this trick in locksmith magazines. Dating back many, many decades.

Falcon used a variation of this to determine if a room key for a motel lock would turn only far enough to withdraw the bolt, or if it would turn all the way around. The one which turned all the way around was the emergency key, and would also withdraw the deadbolt. The room key and the maids keys would not withdraw the deadbolt.

Reply to
Stormin Mormon

This is actually called a Brink Function .... was invented by RR Brink Locking Systems.

BBE had a nice article on it on his TheLockman.com site ...

The Brink Function, Why It Works, How It's Made, November, 2002

.... maybe he will post part of it here ...

Best regards ...

Reply to
M.C.

Item number: 4363122789

Check Ebay...

Reply to
Stormin Mormon
Reply to
Robert Nichols

Actually in real life the Brink Function does not require turning down the end of the top pins. Imagine if you will the geometry involved. A section of a plug through a pin chamber will show how it works best. If the diameter of the plug is altered by two or three depths of cut by removing material on one side of the pin chamber by a cut perpendicular to the pin chamber, that is the only modification needed.

The pin tumbler is wider than the cut depth and therefore will never ride into the side of the pin, it is mechanically impossible. In that way the change key only raises the top of the pin to that modified shear line and only allows the key to turn in one direction while the MK raises it to the plug OD and can turn both directions.

Which side of the p>

Reply to
Billy B. Edwards Jr.

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