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Common Terminology

In this section we look at the common terminology surrounding padlocks. We've divided the terms into three sections for ease of use:


  • Pins

  • Locking Mechanisms

  • General Terminology




Top (Driver)

The top pins (red) do not come into contact with the key, their job is to stop the cylinder being turned - they cross the shear line when the lock is closed and would still do this if the wrong key were inserted.


Mushroom pins are top (driver) pins shaped like cotton bobbins. They are an effective way of making lock picking more difficult as the pins tend to move out of alignment if they are disturbed.


Mushroom pins are shown in red on the diagrams.

You might have noticed that the first pin in the cylinder is a straight pin. This is done to avoid any problems with misalignment as the key enters the cylinder.

Bottom (key pin)

The bottom pins (green) come into contact with the keys. Thecoation of the length of the bottom pin plus the depth of the key cut puts the join between the top and bottom pin exactly on the shear line.

Master Wafer (Wafer)

It might be helpful to think of these as thin pins (yellow). They are used in Master and Grandmaster keyed systems and their job is to provide a second or third shear line that the master or Grandmaster key will be cut to suit.

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