by Raymond » 14 Oct 2008 0:50
Padlocks are almost always more difficult to pick because of this turning force problem. The spring that pushes the bolt out into the shackle also returns the plug to the normal locked position and continues to apply this turning force on the plug in the locked direction. In picking you must balance your turning force so as to offset the return spring force and just enough more that you can feel and set the pins. More force will simply make the pins harder to move but is acceptable if you can feel them set and you do not overlift.
Nothing is foolproof to a talented fool. Wisdom is not just in determining how to do something, but also includes determining whether it should be done at all.