I have a professional interest in lockpicking so I sometimes check on what the sport lockpicking community is up to. One of their rules is to only pick locks that you own which is prudent from a legal standpoint but I’ve also read that this rule is because you may break the lock. It would be difficult to break most locks with lockpicks but there’s plenty that can go wrong. Let’s talk about what can happen to a lock when it is picked.
- The lock can be disabled by popping a floating cap off of a cylinder.
Many locks have a cheap piece of metal covering the bible that clips on and can fairly easily pop off. The worst offender is the Schlage F series. Many locksmiths think that they are garbage locks, I think they’re fine for residential purposes but I agree with my colleagues that when it comes to masterkeying they are trash. If you put a large top pin in one of these locks and then put a key with a shallow cut in that lock there’s a good chance that the floating cap will pop off.
I’ve heard anecdotes about locksmiths who installed Schlage F51 knobs in a building and were constantly being called back to fix the knobs which stopped working because the cap would pop off under normal use. I grudgingly masterkey F series knobs for value minded building managers who have these but I try to use bittings that will not cause the cap to pop off if a blank key is inserted. The pin stack shouldn’t add up to anything over nine, if you understand what that means.
A better choice for masterkeying doorknobs is the Arrow rk11 which has a brass cylinder with no floating cap, though the cylinder’s design is annoying and it’s harder to insert a key into the cylinder than other lock cylinders from other manufacturers.
The floating cap can pop off in a masterkeyed building scenario but what about with lockpicking? Yes, attempting to unlock these knobs with lockpicks, bumpkeys or comb picks can all result in a popped floating cap. In fact there are tools commercially available to locksmiths designed to do exactly this. If the cap pops off and you don’t know what you’re dealing with you will still be locked out. The pins will still be in the lock, it will be much harder to unlock with a key or lockpicks because there will no longer be spring pressure pushing all the pins down against your key and you will have no feedback with lockpicks. If you don’t have a comb pick to push all of the pins out of the chambers you will need to make one at this point or destroy the knob or figure out another way in.
2. Master pins can fall into the keyway
This shouldn’t be possible most of the time but I’ve been to a few late night calls in my time where the victim actually had a working key that just wouldn’t work. Lockpicks wouldn’t work either! The culprit was actually a master wafer that was smaller than the manufacturer’s smallest suggested master wafer. Lock manufacturers build their lock cylinders with certain tolerances in mind and one of them is size of the smallest master pin allowed without causing the lock to malfunction. For a Schlage lock this is .030″. Rules are made to be broken, as they say, and one building in downtown Seattle I won’t call out here was masterkeyed by somebody who thought that rules are for the birds and used wafers as small as .015″. As a result, the wafers actually get stuck in the space between the plug and the cylinder housing. The strange thing is that this building uses a six pin system so they should have thousands of possible bittings that don’t require them to use master wafers out of spec and cause residents to pay locksmiths $150 to come fix things for them in the middle of the night.
Really small wafers can fall out of place in locks under normal use which is why they shouldn’t ever be used, but what about with lockpicks? Things get much more interesting with lockpicking. If you pick a masterkeyed lock and rotate the plug 180 degrees even .030″ pins can fall into the keyway. Under normal circumstances this wouldn’t be possible because there would be a key in the way. The bottom of the key would be blocking the pins from falling out of their chambers. This is especially easy with Weiser locks and their spacious keyway.
3. If you pick a dirty lock you could overlift the pins past where they’ve ever gone in fifty years. Up in those dark lands your pin will encounter grime and corrosion that will sometimes cause it to get stuck. Your lockpick will lift the pin and shove it into some sticky gunk. This could also occur if the wrong key was inserted and it had some shallower cuts than the normally used key. This can be prevented by cleaning your locks out once a year by spraying some tri-flow on your key or directly into the lock. Once the pin is already stuck it will be much harder to clean around it. You can take the lock off and turn it upside down and spray lubricant or penetrating oil into it but that doesn’t help you if you are locked out.
These things can all happen to professional locksmiths and sport lockpickers along with criminals. More interesting things can happen with amateurs though, like breaking a lockpick off in the lock. If you don’t have special tools to get foreign material out of a lock, then you can’t stick the key in and it is disabled.
If an amateur picks a padlock in the wrong direction the lock can be disabled as the top pins will all fall into the keyway and block it from rotating. This is an easy thing to fix if you can lift all of the pins.
That is really all of the ways I can think of that a sport lockpicker could accidentally render a lock unusable. Of course superglue, drill bits, and a million other things can maliciously render a lock unusable.