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Picking Torque

This exercise will teach you the range of torque you will need to apply to a lock. It demonstrates the interaction between torque and pressure which was described in chapter 5. The minimum torque you will use is just enough to overcome the fiction of rotating the plug in the hull. Use your torque wrench to rotate the plug until it stops. Notice how much torque is needed to move the plug before the pins bind. This force can be quite high for locks that have been left out in the rain. The minimum torque for padlocks includes the force of a spring that is attached between the plug and the shackle bolt.

To get a feel for the maximum value of torque, use the flat side of the pick to push all the pins down, and try applying enough torque to make the pins stay down after the pick is removed. If your torque wrench has a twist in it, you may not be able to hold down more than a few pins.

If you use too much torque and too much pressure you can get into a situation like the one you just created. The key pins are pushed too far into the hull and the torque is sufficient to hold them there.

The range of picking torque can be found by gradually increasing the torque while scrubbing the pins with the pick. Some of the pins will become harder to push down. Gradually increase the torque until some of the pins set. These pins will loose their springiness. Keeping the torque fixed, use the pick to scrub the pins a few times to see if other pins will set.

The most common mistake of beginners is to use too much torque. Use this exercise to find the minimum torque required to pick the lock.

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