Saturday, 28 April 2012

Leadbelly, easy impressioning

In my previous post I forgot to mention that creating the marks on the key requires a fairly good amount of force on the key, it needs to be cranked over fairly hard and wiggled quite vigorously. I held mine in vice grips but others use special holders that are somewhat more ergonomic. Key breakage is not uncommon! I struggled so much to get marks on the previous key because of the locks keyway I wondered about making life easier. 

What I did was take a blank and file down each pin position to the maximum possible depth plus a little bit more for good lock. I  built up the edge with lead/tin solder before finally filing and scraping it to look like a blank again. Files and solder don't really mix so I used a box cutter blade mostly with a scraping action (see cabinet scraping). Above is the finished key with heatshrink protector (so I can carry it around to show off).

Below you can see the line of the join between key and solder. The key must be up to soldering temp when you do this or you do not get good adhesion. Adding the solder was easy, but shaping it a massive pain.

The impressioning process was very easy, the wiggling could be done quite gently by hand (no clamp) and the marks could be seen from space. The lead is not ideal when it comes to filing, really I need a little modified nail clipper of something to make the cuts. 


So, this is a key, nothing special. But I made this key, so what? I made this key for an intact lock for which I had no key! An old lock I found amongst some junk that I held in a vice but it could just of well been in a locked door. How did I do this? 

I used a process called impressioning. It is simple in theory but somewhat devilish in practise at least it was for my lock. I bought a few brass key blanks on ebay and set about the task. First watching this excellent video about the process:

Jos Weyers is a world champion and he had a lot of good tips but I really had no luck at all to start with. The basic idea of impressioning is to insert the blank into the lock then crank it around to the left until its motion is stopped. It can't move any further because one of the pins will be preventing it, the pin that makes contact first (mechanical tolerance means one will contact first). You then jiggle the key up and down, unlike the other pins which move freely up and down the binding pin will be held by the pressure of the tensioned key. That pin will rub on the key leaving a mark (an impression). You repeat this turning the key to the right before jiggling and that will make another mark (as it is likely another pin sill rub). You remove the key and file the two marks away reducing the height of the key at that point slightly. With experience you do this just the right amount to take the key down to the next depth in the key/lock's official specifications.

Sounds easy but the marks are subtle, you need a fine file (mine was too course) and you need some magnification. I ended up with a tiny 45X pocket microscope bought on ebay for around £4 and I made do with my file. I wiggled, I jiggled but no marks. I take the key to work and look under a proper microscope, no marks!

After a few days I give it some thought. The lock is a decent one, a Yale and not the cheaper brass one but what looks like a steel one, at least it is plated. The key barely moves in the keyway, hmm. Out with the dremel, I remove material so that the key can move more freely up and down. I do this on all of the upper edges of the cuts on the side of the key. I try again and I get something!!! But the marks I see are nothing like those in the video above. The keyway of the Yale is very wiggly and when the blank is fresh only the side of the pins rest on the edge of the key. Instead of nice little dots I got a sort of bruising on the edges. Really the brass pins are burnishing the brass key slightly. After 1.5hrs the lock opened and it felt amazing! The hard part had really been assessing what was really a mark and what was not, my file is excellent quality but a little too course and I was forever trying to decide of something was a mark from the file or the lock. The keyway also made it difficult but mainly because I was not expecting marks like the ones I got.

I have a feeling that I chose the worst possible lock to begin learning but I learnt a heck of a lot!

Locks or puzzles, or both?

For the past few months I have been learning about lock picking after getting an email from stumbleupon suggesting the website for toool, the open society of lock pickers. And from there I found some very interesting videos by a guy called Deviant Ollam, I'm not sure that is his real name but the videos were extremely illuminating!

I discovered two interesting things; lock sport and physical security. The former is the idea of treating a lock as a mechanical puzzle and the latter is working on how to improve security and exposing problems with locks so that they may be fixed or avoided.

A lot of people would think it is a bad idea to publicise methods that could be used to commit crimes but it is clear that lock picking is generally not the method of choice for burglary and that by showing just how insecure some locks are people are more likely to choose wisely at the hardware store. An example is a small cash box I own, I discovered it could be opened with a small screwdriver and a paper clip in 3 seconds. My colleague could do the same after perhaps 10 seconds, 5 seconds of that was getting instructions from me!

So I have a few picks and a few locks and am learning a lot, it is really quite fun. It is interesting to see locks in a new light, before I thought of them as absolute seals but now I see them simply as devices, each having pros and cons and limits to its security. As my knowledge grows I feel more and more that it is my morals that keep me out than any lock. The average burgular does not have these morals or indeed the skills but he does not need them as he wields a hammer!

Tuesday, 24 April 2012

Very small houses

I really feel that if I had a large workshop (new blog name required perhaps?) with room for all my hobby stuff then I would not really need much space to actually "live" in, some of these tiny homes are really inspirational, especially given that you can often build them yourself for little money.


Monday, 23 April 2012

John Cleese on creativity

I expected this might be inspirational but I was not expecting it to be as practical as it is. There is some excellent advice on creating the right kind of time/space/mindset for creativity. I like the fact that he recognizes the psychological problems that present themselves when one tries to sit down and work on hard problems. It is nice to know it is not just me.