Bumping ehh? Try this:O)

[scorpiac]

I know this would not likely make a lock completely bump proof but it seems to me a perhaps overly simplistic method that should make it significantly more difficult at the least would be to simply key a lock where at least 1 stack has a key pin thats say a 9 and leave out the top pin and spring all together. So when a bumping attempt is made there is no top pin for the energy to be transfered to causing the keypin itself to jump up into the empty space... now the keypin can still clear the shear line when bumped but the likley hood of that key pin jumping into an empty space with no resistance (and i would think it would fly up and come back down really quickly) and the other still spring tensioned top pins all clearing the shear line at the same precise moment would be very slim, wouldn't it? What are your thoughts on this? Am I completely overlooking something here? Has this method been discussed before?

[Stray]

Yeah it has been discussed before... i think

[Deathadder]

What happens when the key pin gets stuck or dirty? Aso, this wouldn't work on european locks. There are so many things that could go wrong with that theory that it makes it impractical, however, i do believe it could be a good DIY job as long as you keep the lock clean (which most people don't) so if you are looking to use it for yourself, go ahead, it would probably work great (just keep the lock clean )

[globallockytoo]

I like how you guys are thinking but still I dont see many practical solutions that are cost effective.

However...I recently thought that perhaps having a rubber bezel or "O" ring between the lip of the plug (barrel) and the inside of the cylinder...might cause the amount of turning pressure to increase significantly on any key inserted in the keyway.

Bumping usually works by tricking the plug into creating a false shearline quickly...and turning the plug quickly...

If you slow down the speed at which the plug is able to turn...this would dramatically reduce the probability of successful bumping, I think.

What do you think?

[Deathadder]

i still like my idea =D

[globallockytoo]

how about you make four (or five if it is a six pin) pins come to the normal stopping distance without a key in or anything, and one that is significantly above the rest, like the picture. the higher one could be randomly placed, (except the front of course) and you could even mix the heights of them all or something... if this doesnt work let me know lol.

I'm not sure about this...it seems that there will be alot of difficulty inserting the key...and if an incorrect key is inserted...it would probably jam...can you explain this a bit better?

[Deathadder]

you know how all the pins come to a resting point inside the lock when no key is inserted right? well this one is just raised above the point at which a bump key can affect it. in essence, the pin is "out of reach". other than its higher resting place, the pin functions in the same way as all the others. There would be no difficulty inserting the key, because the only thing that is different is its a little higher up, it wouldnt jam because of the same reason.

[globallockytoo]

you know how all the pins come to a resting point inside the lock when no key is inserted right?

Obviously

well this one is just raised above the point at which a bump key can affect it.

What exactly is raised?

in essence, the pin is "out of reach". other than its higher resting place, the pin functions in the same way as all the others.

out of reach of what?...if the pin blocks the chamber and is too long to "bump" above the shearline...then any correct or incorrect key, when inserted would either jam (not go in completely) or if it goes in ...wont withdraw

There would be no difficulty inserting the key, because the only thing that is different is its a little higher up, it wouldnt jam because of the same reason.

Explained above

[jiggler]

I know this would not likely make a lock completely bump proof but it seems to me a perhaps overly simplistic method that should make it significantly more difficult at the least would be to simply key a lock where at least 1 stack has a key pin thats say a 9 and leave out the top pin and spring all together. So when a bumping attempt is made there is no top pin for the energy to be transfered to causing the keypin itself to jump up into the empty space... now the keypin can still clear the shear line when bumped but the likley hood of that key pin jumping into an empty space with no resistance (and i would think it would fly up and come back down really quickly) and the other still spring tensioned top pins all clearing the shear line at the same precise moment would be very slim, wouldn't it? What are your thoughts on this? Am I completely overlooking something here? Has this method been discussed before?

This could not work in UK Euro/Oval cylinders used on UPVC doors as the pins are not pushed down like they are in a Yale-type nightlatch rim cylinder. In the Euro/Oval locks the cuts in the key are facing down when you use it. The pins are pushed up by the springs. So no spring means the pin would be down in the bible and the lock could never be opened.

you know how all the pins come to a resting point inside the lock when no key is inserted right?

The resting point is a keyway ward. It cannot be lower at any point otherwise the key could not enter the keyway properly.

The only possible way for this to work is to have the ward raised at one or more pins. But then that pin could not have a deep cut on the key - restricting your keying options.

But to get around it you'd just bump all the pins you can contact and pick the few the bump key has no effect on.

[JackNco]

Take the springs out and replace them with something like a spring loaded shock on a car but much smaller. Might work. Works normal at slow speeds but the force is absorbed when bumped. Something like a piece of memory foam or flexable rubber inside a spring.

Actually thats a bloody good idea.

Im not sure if u have them in the states but u can get a small shiock that fits on kitchen cupboard doors and slows them closing. cost about a quid and woudl work perfectly.

[Deathadder]

I dont know if you guys have heard of this, but there is this kind of rubber, only its porous with little tiny air bubbles in it, and it would probably work great on your idea. All you would have to do is cut out little cylinders of it and put it in your lock in place of the springs. I'll try and find out the name of it, and once i do i'll post it for you. This would be a good DIY thing.

[JackNco]

woudlnt any kind of foam eventualy become compressed and make bumping just as easy?

[globallockytoo]

woudlnt any kind of foam eventualy become compressed and make bumping just as easy?

Thank you! ...You are absolutely correct.

I think the only solution is to remove top pins from the equation altogether...or look for alternative ways to slow down the speed at which the plug can turn.

[zeke79]

For anyone who has not read it, look at Han Fey's Pfaffenhain article. I have been playing with the same pin design and it is very effective in making bumping difficult or altogether not possible in my experience.

The problem I have found so far with their method is the top pins if narrowed down too far can fall into construction holes on the plug and completely block the lock from working.

[d_goldsmith]

woudlnt any kind of foam eventualy become compressed and make bumping just as easy?

Thank you! ...You are absolutely correct.

I think the only solution is to remove top pins from the equation altogether...or look for alternative ways to slow down the speed at which the plug can turn.

Actually, that's not true. Tempurpedic foam will never become compressed. It's been ran over by steam rollers and still regains it's original shape. It was made by NASA.
http://www.tempurpedic.com/TempurCMSVB/company/nasa
You can get a free sample at their website too, about 1 inch x3x4inch. Plenty for filling a hundred lock bibles.