magnetic padlock
This is a padlock that can be made by children
You need a small amount of card, a ring magnet and a paperclip. The most difficult bit is bending the paperclip. Make the box to suit the ring magnet, it should be a loose fit and about twice as thick as the magnet. Took 15 years to design.
This is its predecessor
It is made from a sandwich of dark transparent perspex glued together, the barrel is made of a 1cm length of round steel bar, it has a radial hole with a small metal peg projecting. This rotates with the barrel and jams or un-jams the hasp, you grip the barrel between thumb & forefinger to rotate it.
The hasp has a notch filed in it near one end. To open it you have to know to hold it up to the light, then you can see the mechanism.
coke-can combination lock
Simple combination lock made from a soft drink can with the top removed. Two cardboard rings are made by laminating bits of toilet roll together with PVA, then stuck to the can with small bits of double-sided sellotape
A double lid is made from thin card in such a way that one can rotate inside the other. Both lids have an internal cardboard bump that rotates against the cardboard rings. The lid can only be removed by lining up the bumps.
The internal lid can be rotated independantly of the outer one by means of the oval cutouts in the sides of the outer lid.
This shows the outer lid marked out, the inner lid fitted on the can.
This shows the lid in place, the box can only be opened by rotating the inner lid to the correct alignment with the outer lid
This shows the lid removed
wikipedia on lock picking
safecracking robot
richard feynman on safecracking. Starts about half-way down the page
history of locks
all about safes
useful gadget
animation of lever tumbler lock
my email is davidvwilliamson@hotmail.com
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