Un-natural scratches

[Dr Money]

I remember my friend telling me about a michael crichton book where he describes a train robbery. This guy robbes a money train or something and using his wit completely outsmarts the cops.

Anyway, during the investigation, they deternimed that he picked the lock to some door because there were "un-natural scratches" inside the lock. I read something, i forget where, that talks about this.

My question, is where do these scratches appear? I assume they are caused from the pick and not the tension wrench. I would also assume they would be on the pins. Right? Anyone know?

[Pheniox]

sides of the lock, in the keyway where the tension tool was put in.

On the pins, back of hte lock.

[Romstar]

Forensic anaylsis of a standard lock cylinder after picking, or a picking attempt will show various scratches that are inconsistant with the insertion, use and removal of the proper key.

Where there are a few methods by which one might avoid leaving a number of scratches, there is no way to avoid them all.

The materials used to make most locks are highly susceptable to scratching, and impressions. Brass, being the most common material is easily marked and this is the reason that most keys are made of the same material.

As you examine the marks made by a key you notice they are almost always in the same direction, at the same locations, with a similar amount of force. Characteristics of the lock, such as a slightly misaligned pin, stiff spring or other anomoly lead to very specific markings inside the lock.

The use of picking tools lead to a variety of scratches and markings which are entirely inconsistant with the use of a key.

From the impressions made by the tension tool, to the scratches on each pin made by the pick. Also, as you encounter these anomolies your pick will most likely slip, or jiggle about. Raking a lock is even more abusive to the mechanism, and leaves much more pronounced scratches.

Under a microscope, scratches left by the use of the proper key will match the key very much the same way the lands on a bullet will match the rifling in a gun.

Comparing these scratches to the very different marks left by a picking impliment will show that something else was used in the lock.

Romstar

[WhiteHat]

also see this thread:

viewtopic.php?t=2912

[scrapheap]

Ok, here goes my first post.

I can imagine the tension wrench causing the most scratches, unless you are raking the lock. Prehaps it might be possible to coat your tools in some kind of thin rubber to help avoid them (though it would have to be very thin not to get in your way) and this might cause a loss in the feedback you get from a lock while picking it.

[Varjeal]

Nothing to worry about if you're legally picking the lock. The amount of wear, although perhaps more than a standard key, is still extremely minute.

[hzatorsk]

scrapheap,

Minute scratches inside the keyway as left by a professional locksmith (with good technique) are not visible to the customer as not too many customers use 10x loupes to analyze their keyways for tiny scratches in the brass patina.

So... from a metallurgy standpoint, preventing tiny scratches is interesting. But it is also, unnecessary.

And, generally, unless there was a crime, no forensics specialist would be involved in the first place. If there WAS a crime... I'd just a soon not be the last guy putting picks to the lock. Strangely enough... that sounds like a free ride downtown.

[silent]

Check out "Steal this computer book 3" it has a section on lock forensics.

[Romstar]

scrapheap,

Minute scratches inside the keyway as left by a professional locksmith (with good technique) are not visible to the customer as not too many customers use 10x loupes to analyze their keyways for tiny scratches in the brass patina.

So... from a metallurgy standpoint, preventing tiny scratches is interesting. But it is also, unnecessary.

And, generally, unless there was a crime, no forensics specialist would be involved in the first place. If there WAS a crime... I'd just a soon not be the last guy putting picks to the lock. Strangely enough... that sounds like a free ride downtown.

That's a nice assumption. Like a lot of other assumptions, it is also wrong. In most cases, it is not necessary to use any sort of magnifying instrument to see the scratches.

As a matter of fact, the plainly visible scratches are often the sort of thing one looks for to INDICATE a crime, and therefore bring a forensic expert into the investigation.

Obviously, if a plainly visible crime has taken place, the locks will be examined in closer detail, and this often means disassembly, and metallurgical analysis as well.

You're right about one thing. If they know the last person to have picked the lock, that's at least going to bring some questions.

Romstar

[Wesson357]

The FBI toolmarks division has some of the best people and equipment in the world for identifying things like this, they can even get specific as to what tool by what manufacturer made the marks.

Its pretty amazing.

[Romstar]

It's nice to know that somebody else knows about this stuff.

Romstar

[PickPick]

I've some doubts about determining the manufacturer. Sure you can tell which kind of tool was used, as the dents from a mechanical pickgun look different than pick scratches or the mess that an electric pickgun leaves behind. But I don't think that the scratches between say HPC2000 and Falle differ enough to tell them apart (but the Falle turning tool probably leaves some very distinctive marks). And then you probably wouldn't account for modified/filed down/rounded off picks and so on.
To really tell the different picks apart, you'd need metal from the picks imho and because they're harder than the lock, they won't leave a lot of metal behind.

[reg]

If tools used are new and unaltered their marks could probably differ enough.
I'm still with pickpick, though - most people do sand off their tools which has two effects:
1 (intended) the tools can be inserted more smoothly
2 (goes with it) there are no sharp edges that first lose some material that could then be left behind in a lock.

[Eagerpicker]

It's nice to know that somebody else knows about this stuff.

Romstar

Hehe, everybody's an expert since Jerry Bruckheimer made "CSI" and "CSI Miami", and of course the Discovery Channel airs interesting documentaries on forensic science.

[hzatorsk]

Romstar,

From a crime scene standpoint you are right. I understand your point and it is well taken. I am going to to disagree with you to some degree...

My presumption was that the original poster had no illegal intent and was just curious as to whether locksmiths worry about damage to customer locks. Generally, that answer is "No". And customers do not notice tooling marks from a picked lock. If so... the technique is wrong.

My premise was from the practical day to day activities of a locksmith.. Not from what a crime scene investigator would find investigating a crime scene. I presumed (perhaps incorrectly) that amateur work would indeed be obvious.

Once again... "good locksmith + good technique + no crime commited = no customer complaints about scratches!"