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Ball bearings

PostPosted: Sun Aug 04, 2019 3:36 pm
by Rjohn16
Hi, I remember seeing ball bearings in high usage locks to reduce key wear. Would those help reduce the odd of success in bumping ?

Re: Ball bearings

PostPosted: Sun Aug 04, 2019 5:24 pm
by MHM
It's all about energy transfer so it depends where the ball bearings are. If they're in direct contact with the keypins in between the keypin and the key as per jail moguls, they *might* make bumping harder simply by adding some more randomness to the system...but not much. Think about a Newton's cradle...it works just as well with one stationary ball as it does with five.

If you can suspend the balls somehow either above or below the keypins such that there is an airgap, then yes, definitely this would make bumping harder. Even more so if that airgap was somehow randomised in size between chambers.

And if you make the ball bearing part of the top pin assembly (one manufacturer puts a captive ballbearing inside a few of the springs, at random) then this will also make bumping less reliable.

Re: Ball bearings

PostPosted: Sun Aug 04, 2019 6:14 pm
by 6275LA
Ball bearings in all chambers run the risk of "combing" where you simply lift all stacks so the ball bearing is at the shear line. In short, it makes picking the lock much easier. Very old Corbin cylinders were keyed like this.

Later, Corbin started only putting ball bearings in the first two chambers to reduce the risk of combing. The pins in the first two chambers get the most wear as the entire key blade has to pass them before the key stops. Ball bearings in the first two chambers offers the ideal balance of wear resistance and security.

New advances in alloys made for stronger bottom pins, reducing further the need for ball bearings. New Corbin cylinders don't have them.

I remember reading somewhere about a locksmith who was called frequently at a bank to service the vault day gate cylinder. Keys stopped working, so he repinned it. The same thing happened a few times before he put two ball bearings in the first two chambers. The wear slowed down considerably after that.

Re: Ball bearings

PostPosted: Sat Aug 10, 2019 5:58 am
by Rjohn16
I thought that maybe the balls rotating would lessen the amount of force transferred to the pins.

Re: Ball bearings

PostPosted: Wed Dec 11, 2019 6:27 pm
by GWiens2001
Late to the party, but perhaps putting the ball bearing above the driver pin and with a shorter driver spring might work. The bearing would be above the driver pin which is blocking the shear line, so the bearing being bumped would not clear the shear line, nor would it make picking easier by acting like an extra wide shear between pins and would not be susceptible to comb picks.

Just my 2 cents.

Gordon

Re: Ball bearings

PostPosted: Fri Dec 13, 2019 3:12 pm
by mastersmith
I used to open Corbin cylinders with a pick gun regularly. They had bearings in them from the factory. There was no appreciable difference from cylinders without the bearings. Both popped right open.