What methods of lock picking does this work with? And does it work on a lock that’s still in use? Raking would probably be pretty distinctive but it seems like sticking a key in there would erase any faint marks left by single pin picking and bumping would look like normal key use.
Probably not. Not in a standard door lock like Kwikset or Schlage—they have a published standard for the maximum distance between one pin and the next, called MACS or Maximum Adjacent Cut Specification. This is to prevent the exact problem you describe. For example, a standard Schlage key has a MACS of 7.
Nevertheless, an individual can key a lock any way they want, and many of the challenge locks used between lock sport enthusiasts have rather grotty key action because of things like exceeding MACS.
Even without exceeding MACS, some simple things can be done to an existing lock to greatly complicate picking: Related to your line of thought, one can use a very deep cut near the bow (base) of the key, followed by a shallow cut: this results in a very long key pin in the front of the keyhole hiding a very short pin, and it is quite difficult to get a pick behind the front pin without oversetting it.
In addition to this, you can add security pins such as spools and serrated pins that will hang up in the wrong places and impede bumping and raking attacks.
If you like lock smithing you will enjoy watching this guy.
Both single-pin-picking and raking leave distinctive marks, which are slightly different from each other. Sticking keys in and out of the lock will erase these marks, but just one use of the key won’t do it. It might take 20 or 30 times to do it.
The truth is often stranger than fiction. At one point he was stealing 70k per year with his specialized payphone lock picking device. Pretty hard to imagine someone making a living at that now.
Thanks. I can’t really see how SPP would leave much of a mark especially compared to the more ‘violent’ action of inserting a key, but I’m pretty gentle, I guess some people aren’t. I guess I’ll put my plans to pick the lock at Fort Knox on hold for now.
Imagine this. The top edge of the blade of the key consists of wide flat surfaces, like a plastic spatula. In comparrison, the pick is made of a harder substance and the tip is narrow and curved, like a teaspoon. Try flipping a pancake with a teaspoon and see what marks it leaves on the pancake. That’s a bit like what you see with single pin picking. Now take a butter knife and whack the pancake from above, making it spin around in a circle. That’s the marks you’ll see from raking.
Thanks for sharing that. I had never heard of him/his crimes and I wondered how it all turned out. Did a little googling and found that he was identified and arrested at home in California less than a year after the article you cited. Did 3 years and got off with a tiny bit of restitution according to the article I found.
I can think of one possible trace that might be visible on superficial inspection, but it would require a specific clumsy error on the part of the picker. If the tension wrench slips out while the picker is overtensioning, it might leave a curved scratch at one or both ends of the keyhole. Scratches from fumbling with a key would typically be straight, I think, so you might be able to tell the difference, if you were looking for it. I’ve never seen such a scratch, so this is speculative; maybe sbunny8 could comment on how plausible it is.
(The tension wrench would probably also leave scratches on the bottom of the keyway, but I think you’d have to disassemble the lock to get a good enough look at them.)
There’s a short story by Bruce Sterling titled “Jim and Irene” based on James Clark.
Thanks for posting that article; I knew he was captured but was wondering what happened afterwards. Pretty light sentence all things considered; I wonder if there was some quid pro quo for demonstrating his lock picking device(s) to the phone company…
I think somehow the idea of detecting scratches from an attempt to jimmy a door morphed into the idea that scratches from a lock pick could be detected. There aren’t any tell-tale signs of picking that are distinguishable from scratches from key fumbling. The point of such detection is that someone has been in the room that shouldn’t be there. Given that possibility the same actions should be taken whether there are any indications of picking or not. Are you gonna just walk in a room where the bad guy is waiting with a revolved loaded with 63 bullets just because you don’t see scratches on the lock? Of course you are, bad guys can’t hit anything even with 63 shots.
I think we must be talking about two different things here.
#1 scratches inside the lock, such as marks on the pins, visible under magnification. YES they are there are they are distinctive, but they are not conclusive.
#2 scratches on the outside of the lock, visible to the naked eye, without disassembling the lock… Well, if such a thing exists, this would be the first I’ve heard of it. I’d say it’s fantasy.
I thought we were talking about #1.
Or perhaps the fact that scratches made by a pick INSIDE the lock are detectable morphed into the idea that scratches made by picking OUTSIDE the lock are visible.
I’m not so sure scratches on the interior of the lock can be determined to be from picks instead of the wrong key or a broken one. Even if so it’s not something our hero detective would be able to determine with the naked eye. Maybe if he’s got a fiber optic camera with him he could take a look, but I’ll bet most locks are scratched up considerably internally just from keys. And I’ll go back to the other point, if someone might have already entered that room surreptitiously you can’t just trust your examination of the lock to determine that hasn’t happened.
However, if I were a private dick, instead of just a dick, I’d always use that line before entering a room so I could pull my revolver from my shoulder holster under my trenchcoat, push my fedora down, then kick open the door and run in firing.
Always? Always?
Hi Honey! I’m home! Bang Bang Bang!! 
But that’s the whole discussion above. Pin picking means using something like an L-shaped small but very tough implement to move the pins up one at a time. As you move one up, you could be scratching the side of adjacent pins.
A key will not scratch the sides of the pins, as the bottoms of pins slide along the edge of the key - nothing really touches up the sides of the pins in normal use.