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Minimal Movement Method
Posted 18 December 2007 - 08:02 AM
I'm trying to find a good explanation of exactly how to do the minimal movement method, and yes I did search. I searched for "minimal movement" here and got over a hundred hits in sixty-seven threads and I looked into all the threads. In every single instance when anyone here asks for the minimal movement method to be explained, the only answer offered is a variation of "search, it's been discussed here dozens of times" or "the toools site explains it fully". In none of those sixty seven threads did I see one of those dozens of times it has been explained. When I tried to access the toools forum, it informed me that I was denied access and had to be invited by a member of that forum to register.
I did find one helpful post that drew a picture of exactly how far to file the tip and shoulder (one half tooth/one pin width) which leads me to believe that the technique might be to insert the key all the way with the pins resting in the bottom valleys, so maybe bumping them from that position for one-half a tooth length will result in bouncing the pins the rest of the way up to the shear line (?) However that still leaves tension/angle of hit/etc to guesswork.
I am a moderator on a website with over 74,000 members and 1.6 million posts so I know how to search. Yes I've told noobs there to search dozens of times, but at our site the irony is that it has become so huge that a search there will now typically result in a gazillion hits that would take days to surf through posts that have the search term followed by someone posting "do a search" while never finding the actual info... so I do understand the frustration of newbies sometimes and have gotten a little easier on them.
I have tried here, but can't seem to get a hit that finds one of those original "dozens of explanations". Would someone please take the time just this once to either explain it; or alternatively, to post a simple link to one of those dozens of posts that explains it?
Posted 18 December 2007 - 05:22 PM
The pull out method involves taking an unmodified bump key (or depth key, as in this case they're synonymous), inserting it fully into the lock in question, pulling it out one pin (click), and then bumping the lock by applying light turning force on the key and striking the head of the key with light force but appreciable speed.
The resting position of the key in the lock prior to bumping is set up such that each pin is right in front of a "ramp". Thus, when the key lurches forward, the energy is transfered to the pins at an angle. However, the pin stacks are contained in holes drilled into the metal plug, and thus only the vertical component of the force is effective. The vertical force is transfered through the pin stack, quickly popping all the top pins above the shear line simultaneously, allowing the lock to turn as though the proper key had been inserted. The further motion of the key into the lock, which may push the bottom pins above the shear line, should occur too late to affect the lock opening, or be too insignificant (due to small ramp and peak size) to cause the bump to fail.
The minimal movement requires the removal of an equal amount of both tip and shoulder from an unmodified bump key. This allows the key a tiny bit more travel into the lock from it's normal resting position. This new, fully inserted resting position finds the pins just slightly touching the each ramp, not including the one on the very front of the key. The key is inserted into the lock to where it's original resting position would be. Due to the valleys cut in the key, it should find this position very naturally. The key is then bumped as in the method described before, but with even less force, as the key has a much shorter distance to travel. The pins, each beginning in their respective valleys, are just barely tapped by the ramps following them, and the key rebounds, sending the top pins jumping out of the plug and into the shell of the lock as previously described, allowing the lock to be turned.
The minimal movement method, is, in the end, a much more effective way of doing business, assuming that you're competent with a file/grinder/key machine, etc. The problem is, most people are not.
The benefits of minimal movement over pull out includes a smaller chance at doing damaged, due to smaller force requirements, and the guarantee that all of your pins start out at a point that is the lowest depth... occasionally, if a large bottom pin is in the first pin position in a lock, the pull out method will not be effective because the resting position one pin back leaves this large pin above the lowest depth, resting on top of the larger front peak. By an large, however, pull out is indeed effective, and for most people the disadvantages associated with it are far outweighed by the fact that the keys require no aftermarket modifications.
Any more questions, PM me.
Posted 12 February 2009 - 12:18 AM
I've never actually successfully done a mini movement bump before but have tried many times on my KW1 house lock. The pull out seems to work well on my house though.
Also just wondering if anyone else has encountered anything like this: The filed down spare that I was bumping regularly on the master No. 3 all of a sudden stopped working. It would take 15+ bumps to get it open (using the pull out method) wondering of maybe the metal of the key is too soft and maybe its going in too deep now or something. Any thoughts?
Posted 15 February 2009 - 12:42 PM
The minimal movement method is a bit more difficult to master for any sort of lock, primarily due to the tight tolerances necessary in modifying the vanilla (unmodified) depth key. Once a properly modified key is made, it is much easier to use, due mostly to the fact that the process is quickly repeatable.
The vast majority of keys that you're going to encounter are either brass or coated brass. In either case, they are subject to wear when being used in a fashion that's more strenuous than their original purpose. Thus, impact between the face of the peaks on your key and the individual pins can erode away at the peak, up until the point that the key will no longer function. This is why it's very important to not use your original master set of keys, and only use copies, assuming that you're bumping frequently.
Posted 15 February 2009 - 08:22 PM
Minimal movement technically works on all padlocks. However, since the plug is very loosely seated in the lock for most of the common Master brand padlocks and clones, the pull-out method is easier to make effective as the wiggle of the plug is negated by the action of the key being slammed home....
Hrmm -- i get back from a long weekend and see someone by the name of 'theopratr' posting. Who can this be ?
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