Depth affecting bumping

[Chrispy]

Has anyone found that locks with a pin (any pin, even one) bigger than a #6 pin is a lot harder to bump? I've been experimenting with different pin combos and found that if my combo has a 7, 8 or 9 pin in it, it's freakin' hard to bump compared to a combo such as 32354.

When the lock has the above combo (32354) it takes two or three bumps to open. With a 46574 combo, it took almost 10 to 15 bumps to open.

I'm assuming this is because the longer pins bump past the shearline when the others (smaller pins) bump to the shearline.

Comments?

[skold]

You have the right idea.

The larger the pins, the more likely they are to "overbump" and get trapped.

This is why you use less key tension while doing locks that you can identify to have larger pins.

[keysman]

I have been watching the bump threads for a few weeks now. and I have noticed a common thread with people who are having difficulty bumping .

You are approaching this in the wrong way .. Bumping is NOT picking,
any more than using a pick gun is picking .

Here is the secret .. tension has almost NOTHING to do with your sucess or failure. actually applying tension before the pins jump is just counter productive.

When using a pick gun or bump key, tension is not a major factor ,TIMMING is everything!

The idea here is to allow the pins to 'jump" . while the bottom pins and the top pins are seperated you apply a small amout of tension to turn the plug. The trick is to get to turn the plug during that fraction of a second when the space betwen the pins is at its widest.
Check some of the vids that are available that use the pool ball anolgy

[Dimmy Locks]

Having some success ( not as much as I'd like) with bumping there are some observations i'd like to make on my progress so far, and in no particular order of importance:

1.Timing IS important I totally agree. ( practice makes perfect)
2. any "bouncing" contact between key and lower pin ( 2nd strike while top pin is out of contact) will cause the bottom pin to follow the top pin which is counter productive. (I'm experimenting with different peaks to work out the best shape to acheive this).
3. pin size DOES matter. Top pin on a no.9 stack has to travel very little to pass the sheer line (most cases no travel required which is a hindrance)wheres as the top pin on a no.0 stack has a long way to go to reach the sheer line. Thus, pin no.9's top pin may well be on the return ( aided by stronger resistance from the spring before pin No. 0 has cleared the sheer line) supposition here, I have no evidence to support this theory as yet.
4. The billiard ball anology is only partially right. Yes it demonstrates clearly Newtons Law, but those balls are of EQUAL weight. Pin weights vary, as does the resistance along their sides ( miniscule differences I know, but I mention it to show Bumping is not an exact science).
5. Not all the force will be transfered from the lateral to the vertical, some lateral force must be effecting the lower pins by pushing them away from the direction of the strike and they then will only rise vertically when they slap against the pin tube. the amount of this side slap and the timings must differ from pin to pin and must influence the way the forces act upon the top pin. ( Afterall, as pickers we exploit these differences in tolerances everyday).
6. Contact between key blank and all lower pins must occur relative to the pin size. ( I have no factual evidence of this but it would answer y a bump key will bump a lock, replace a pin with a no.9 and it wont bump until u file the contact point, then it will bump, only to fail to bump same lock with original pin refitted).

I know some will say I'm possibly trying to analyse bumping too much, but I did say I was going to research this and I've still got 25 spare blanks to go <g>
the fact is though, these are all mechanical actions, and as such, it should be possible to design a "BUMP GUN", that is totally reliable and effective. Hitting a blank with a piece of plastic with a rubber stopper is all well and good but carries with it a healthy portion of luck.

all critisism and counter arguments gratefully received, but please make them on your own observations or understandings, not on supposition unless you say as much.

[keysman]

Yes I agree with you, you are reading WAY too much into this.
I won't go into detail about my experience with bumping, but Matt Blaze wrote paper years ago about it, and I had used similar methods with varying success before that.

While on a very technical level I would assume you are correct with the way various forces act with and against each other.
In real life situations it doesn't matter, the principles are the same as a pick gun and I have not found pin length to be a major factor.
I never heard of cutting the depth below a 9 until recently, and have had almost 100% success rate with a "factory” 9 with 1 or 2 hits.

You can modify the key in all sorts of fancy ways, some will actually improve your chances, but the fact is: if your timing is off, the lock won't open.

[vector40]

I'm a little curious about the double- or multiple-tap method that Barry seems to use in many of the videos.

[devildog]

Matt Blaze wrote paper years ago about it

Huh? Where? How could I have missed this?? (I take it it's not on his usual site)

[keysman]

Matt Blaze wrote paper years ago about it

Huh? Where? How could I have missed this?? (I take it it's not on his usual site)

Sorry my mistake , it may have been the toool site , been, a few years since I read it. it was well done and very descriptive. I think I have confused a paper Matt Blaze wrote about decoding master key systems around the same time,