by Keyring » 20 Nov 2005 11:15
Well, if you are talking about a pin cylinder lock, then just think... Until the right key is put in, then all the bottom pins are at the same lowest possible point and therefore not able to provide information to the 'gel'. The best you could (theoretically) do is to find a way (thin piece of wire?) to hold all the pins fully up, and make a mold of the keyway, to find out the shape of a restricted blank for example.
I don't fancy your chances though.