You can use this to copy a cylinder lock key within minutes. Especially great if you have a key that says 'do not copy' on it. You will need:
Access to the key (for a few seconds)
A drinks can or other thin metal
Ruler or other hard blunt edge
I have copied a master key for an entire office block doing this and it worked fine.... I have also copied a Yale lock key for a lock which I have been having trouble picking.
Step 1: Copy the key - quick!
Get a copy of the key using either:
Scanner - easiest
Camera - you must have a scale present in the picture (ruler etc)
Impression in bluetak or clay, then scan it or photocopy it. I personally would try and highlight the impression with tipex or something first to ensure a good print.
Print 2 copies of it in the correct scale so that you have two 1:1 copies of the key
Now roughly cut the copies out. Don't worry about cutting each tooth properly, just leave excess paper around it all.
Step 2: Thin Metal
Take a drinks can/tin and cut a rectangle big enough to stick the key to, or any other thin metal. I have included picture of me copying the same key on a drinks can and a fish tin!
Stick 1 cutout key onto it.
Step 3: Cut the copy
Cut the new metal key copy out. You need to cut it leaving some excess metal around the teeth area, we will need the excess later!
See the second picture if you are unsure what I mean....
Step 4: Make the groove
Take another key with a groove in it, it doesn't have to be the original, we are going to use the groove in it to create our groove in the copy.
Now line the groove up with your printout and force a groove into your new copy using a ruler or something thin and blunt. Press the ruler down and whilst holding it down flatten the sides which will now be sticking up in a V shape. See the pictures for detail.