Plug Modding: Lefty Loosey, Righty Tighty

[Schuyler]

Thats acually pretty clever some times the simpliest salutions are the best i was thinking about this the other day. My salution was very complicated though. Like using a mutli function lock like a sidwinder lock in which the pins would lock the door and the scribed full key would unlock it.

It's an interesting balance, honestly. This very simple method has it's own failings. You can't have a master key that would turn it in both directions, as driver pins would get stuck in either direction on the shelf of the filed down chamber.

That said? The level of complexity to make it operable in all 3 important ways would arguably be an order of magnitude beyond this.

So, simple can be great, but rarely does everything for you.

[mkultra23]

wheres the pics?

[copeman]

this exact type of plug modification was in an old locksmith ledger and was used so a key could be given to said employee to lock up at night but not be able to enter without the owner or manager, i will see if i can find the issue in my shop in the morning.

[Schuyler]

wheres the pics?

good question - I will go digging!

[Schuyler]

Restored. I'm glad you noticed, I believe a LOT of my pictures that are floating around this site have been down for a while. They are all re-uploading now.

[mkultra23]

Cool Schuyler. I know this will come in handy at some point. Nice technique.

[straightpick]

What you have there is called a Brink's function. Corbin Russwin developed this a ways back for the R. Brinks Company who wanted this on some of their security equipment. Basically, the cylinder is milled 2 increments deeper on one side, the ramp is actually flat. The cylinder is handed, that is, for the closing function the ramp has to be milled on the correct side so the plug rotates in the closing direction with the closing key. The master key, two cuts higher, allows the cylinder to turn both ways. The ramp is always cut on the last pin hole to minimize wear.

[Benesato]

Do you know what kind of wear could be expected, straightpick? I would have thought after maybe 5-10 years the bottom pins would start to wear out given that they've got to slide upwards against the top pin and its spring. Then again, top pins survive decades of wear sliding against the barrel, so I suppose I may be overestimating the wear.

Benesato.

[darklighterz7611]

I'm just a bit curious, so could some of the more knowledgeable people on here tell me what would happen if the groove filed down was very deep and a plug spinner was used?

The way i see it is that to pass this situation the plug would have to spin so fast that the pin defied gravity for up to a quarter of the plug. I didn't think a spinner could turn the plug that fast, though i am a relative noob

Thanks

[mh]

Hmm... I'm trying to figure out why this concept would allow for a full 360 degree turn in one direction. Wouldn't the rotation stop at about 350 degrees when the side of the key pin that's at the correct shear line hits the side of the corresponding driver pin that's inside the ramp now?

Cheers
mh

[darklighterz7611]

Hmm... I'm trying to figure out why this concept would allow for a full 360 degree turn in one direction. Wouldn't the rotation stop at about 350 degrees when the side of the key pin that's at the correct shear line hits the side of the corresponding driver pin that's inside the ramp now?

No because the key which uses this new filed 'ramp' has a lower bite in the key so the keypin sits at the new filed shear line which is lower than the actual plug shear line. Hence the groove is for the driver pin only.

[mh]

yes but Shuyler had added a second ramp for the other direction at a second position, and there the key has the original bitting. And I think there the driver pin would hit the key pin from the side.

[darklighterz7611]

Sorry i should have worded my last post better,

Basically it would turn 360 degrees in the right direction (locking or unlocking) whatever the key was designed to do.

In the other direction your right, you would only achieve like 350ish degrees but it is this direction which you are trying to stop. at the last second the key pin would block the driver pins path. hence one key for opening and one for locking up.

Though i think the yellow key should be cut to be a master key (file down the 4th groove to match the green key) as why would you give anyone the responsibility of opening if you didn't trust them to lock up?

[mh]

Here is what's confusing me:
(In the picture above, I'll number the pins from 1 to 5, 1 at the left.)

The ramp at pin 2 allows this key to turn the plug counterclockwise. If you try to turn it clockwise, the driver pin at 2 will immediately block against the plug, as it's not pushed up far enough to the original shear line.
So far everything is fine.

But now turn the plug counterclockwise by -say- 350 degrees.
The driver pin at pin 4 will now enter the other ramp in the plug, the one at pin 4. And then it should hit against the side of key pin 4 and not magically lift up.
Or does it lift up, because the pins have beveled edges? But then this would work only in rather sloppy locks where the pins have wide bevels in the first place, and it might not be very reliable over time.

Cheers
mh

[FarmerFreak]

But now turn the plug counterclockwise by -say- 350 degrees.
The driver pin at pin 4 will now enter the other ramp in the plug, the one at pin 4. And then it should hit against the side of key pin 4 and not magically lift up.
Or does it lift up, because the pins have beveled edges? But then this would work only in rather sloppy locks where the pins have wide bevels in the first place, and it might not be very reliable over time.

I recognize the plug from cheap knobs (EZ-set/Defiant). So in this case the cylinder can't/won't turn 360 degrees to begin with. Only 90 degrees either to lock, or unlock.

If you were to do this on a better lock you would certainly have more to think about wouldn't you?