Bumping a lock with a 9 pin??

[ben_p]

Hello, I've recently gotten curious about lock picking and have been looking into the use of bump keys. While thinking about bump keys I was looking at a set of master keys that I legitimately have in my possession. On those master keys there are some pins that are cut to the 9 depth and some pins that aren't as deep which made me wonder...

If a lock has one pin that goes all of the way from the deepest cut to the shear line could you bump it??

If yes, would it be possible to have a pin from the deepest cut to the shear line with nothing (no second pin or spring) on top of it to prevent bumping?? This would get rid of Newton's law because the gravity lowered pin would be the only thing that the key would strike thus the pin would jump past the shear line and block the plug from turning.

[dmux]

thats why the optimal bump keys are actually a 10 10 10 key, but key cutters cannot cut to a depth 10 because there is no such thing but they are just a hair deeper than a 9 cut and they will work

[maxxed]

thats why the optimal bump keys are actually a 10 10 10 key, but key cutters cannot cut to a depth 10 because there is no such thing but they are just a hair deeper than a 9 cut and they will work

I'm not sure where you get this info, I have no trouble cutting 10 10 10 keys

[dmux]

thats why the optimal bump keys are actually a 10 10 10 key, but key cutters cannot cut to a depth 10 because there is no such thing but they are just a hair deeper than a 9 cut and they will work

I'm not sure where you get this info, I have no trouble cutting 10 10 10 keys

ahh disregard, im sure im wrong, i dont have any key cutters that is just what i have heard

thx for the correction

[JackNco]

i like the idea of having a pin with no second pin or spring. im gonna have to try this see how it works

[n2oah]

i like the idea of having a pin with no second pin or spring. im gonna have to try this see how it works

It creates an unreliable lock.

[ben_p]

OK, it was a bad night, I couldn't sleep but did think about this some...

The whole Newton's law thing is great but if the bottom pin has more mass than the top pin then the bottom pin will continue moving upward slightly because it won't be able to transfer all of the momentum to the second pin. This would allow you to have a top pin and spring but I believe it would still cause issues for bumping because the bottom pin would jump past the shear line and cause binding.

I tell you, this lock security stuff has really gotten me. I lost a lot of sleep last night designing locks, and then breaking them, in my head last night. It's probably nothing someone else hasn't thought of, but it's something I haven't seen yet.

[Wrenchman]

Well, hello ben_p

And welcome to the site, looks like you have some good ideas in that head of yours!

I´m not good at math, so I can´t help you with the Newton thing, but the (no second pin or spring) won´t prevent picking, it´ll just make it one pin less, I´m sure it can´t fool a real lockpicker!



Wrenchman

[ben_p]

Wrenchman -

Thank you. I look forward to learning a lot more and am sure I'll have tons of questions for the users on the site.

As far as preventing picking, that's not what I was going for. I know a picker won't be fooled and everything would be easy for him/her since the pin is in a set state by default but this should prevent bumping, or at least decrease the odds of a lock being bumped.

[JackNco]

OK, it was a bad night, I couldn't sleep but did think about this some...

The whole Newton's law thing is great but if the bottom pin has more mass than the top pin then the bottom pin will continue moving upward slightly because it won't be able to transfer all of the momentum to the second pin.

I think thats wrong as most bottom pins are larger. or more accurately have a larger mass. especially where spool pins are concerned. it can transfer the energy but will move the top pin with less mass further than it would the lower pin with more mass.

John

[ben_p]

OK, it was a bad night, I couldn't sleep but did think about this some...

The whole Newton's law thing is great but if the bottom pin has more mass than the top pin then the bottom pin will continue moving upward slightly because it won't be able to transfer all of the momentum to the second pin.

I think thats wrong as most bottom pins are larger. or more accurately have a larger mass. especially where spool pins are concerned. it can transfer the energy but will move the top pin with less mass further than it would the lower pin with more mass.

Correct, but if most of the bottom pins are well below the shear line the extra movement by the bottom pin would leave some room to turn the plug. If the top of the bottom pin is right at the shear line then there is no extra space for the bottom pin to jump before it binds.

[Shrub]

9 Pin lock?

8 Bump keys will defeat your idea,

[ben_p]

9 Pin lock?

8 Bump keys will defeat your idea,

I'm not sure I know what you mean by that but yes, if someone takes the ridge off of the key that would push the pin that's flush with the shear line up they could bump the lock. The benefit is you're starting to make the number of bump keys an attacker would require increase by an order of magnitude.

You are correct though.

Bumping a 6 pin lock would require trying up to 6 bump keys. Bumping a 6 pin lock with 2 pins at the shear line would require trying up to 15 keys.

[Shrub]

6 Pin lock only needs 5 keys but thats the most simple way of defeating your princible im afraid but right now im not in the mood for typing out the full details of why,

Fair idea but if it worked well would only work on normal cylinders and not euros,

Theres also the mathmatics regarding the space available in the plug and chambers to allow for example a key with a very low cut to actually pass under the single pin,

Dirt, grease etc would also help lock the lock up, if the locks full of muck or if the owner has filled it with anything they think will lubricate a sticking lock from oil to vasealene to super glue (i kid you not!!) the insertion of the right key would give a good possability for the single pin to get jammed in the chamber, start giving clearance to counter that fact and the lock is likely to jam up anyway as a tilted pin is higher than a level pin thus the plug not turning,

The best solution i have seen is to not drill the chambers through at the top pin diameter that way the top pins at rest are in a counter bore and the smaller bottom pins push up through the counter bore and then lift the pin, if the two pins arent in contact anyway they cant be bounced,

It is after all the transfer of energy that makes bumping possable, the removal of the top pin is just the same as having a gap, if they arent touching they wont transfer the energy,

[raimundo]

If a key turns hard, its cut too high, if you must cut a duplicat from such a key, you can put a piece of thick paper around the keyblank before clamping it in the jaw of the cutter, this will raise the part being copied, and cause the part being cut, to be cut deeper, So if you put a 99999 depth key in the stylus jaw and cut on a blank that is raised by the thickness of a piece of heavy paper, You have a bump key cut just a bit deeper.
When copying a key that opens the lock easily, but has a trick to get it turning,(trick, meaning a jiggle) this key is worn or cut too low, and can be raised up in the stylus jaw of the machine with a piece of paper, then copied and the copy of the keyand the added width of paper can fix the fit of such a key. (perhaps only if the keyfitter has some experience with impressioning.)