Forget lock picking, clone/copy the key and be a spy

Step 5 Make the final cuts

Now that you have the correct grooves, you can line up the key with the second printed copy, at this point you will need to cut the second printout exactly around the profile of the key (teeth included). Now it will become apparent why we left some extra on the teeth; the groove will have shortened the height of the key and so the teeth now need to be cut higher up on the metal.

Cut the teeth with continual reference to the printout. This is the crucial part, it must be very accurate. Make sure the teeth are not slanting to one side, if this is the case then the thin metal may slide down the edge of the pins and not push them up. Use scissors with a good pointed cutting end and try to cut only using this end.... this allows you to get quite accurate cuts without manoeuvring the scissors around risking bending the teeth.