Security Pin

A security pin is a modified version of a driver or key pin in a pin-tumbler lock that makes manipulation more difficult. Security pins are commonly designed to prevent lockpicking, but are also designed to resist decoding, impressioning, key bumping, and other compromise techniques. Similar modifications to components in non-pin locks are also common, with serrated components being the most popular in both wafer and lever locks. Combination and disc-detainer locks commonly use false gates to prevent manipulation.

Principles of operation

Security pins are designed so that use of a tool other than a key will trigger the pins and lock one or more pins at the shear line. This can be due to individual manipulation of components or tension on the cylinder. When triggered, security pins bind between the plug and cylinder, blocking the rotation of the plug until tension on the cylinder is released and pins are dropped back to their resting position.

Types of security pins

Common mushroom design.
Common spool design.
Hybrid design.
Common serrated and "spoorated" designs.
A disc design with false gates and serrations.

Mushroom: A driver or key pin with a bevelled cut around their circumference, resembling a mushroom shape. Driver pin mushroom designs are much more common, but companies like Mul-T-Lock and ABUS use them for key pins, as well.

Spool: A driver or key pin with a portion of the center removed, resembling a spool or barbell shape. It triggers when the center of the spool is caught at the shear line. "Barrel" pins are double spools. "Gins" are off-center spools, similar to mushrooms.

Serrated: A driver or key pin with light serrations around the circumference of the pin. It triggers when a serration is caught at the shear line.

Hybrid: A combination of the previous three designs. For example, "spoorated" is a spool pin with serrations on the outer edges of the pin.

Gallery

Security pins from Mul-T-Lock Interactive, Schlage residential cylinder, and Goal V18.
An American Lock 1100 serrated key pin.
KABA Gemini; serrated key pin.
LIPS Octro security pins (key pins).
LIPS Octro security pins (driver pins).
Medeco Biaxial; mushroom drivers (gold).
A Medeco Biaxial pin with false sidebar groove and anti-decoding ring.
Medeco Biaxial; pin with anti-decoding ring and micro-milled sidebar slot.
ASSA Twin V-10; double spool driver pins.
ASSA Twin V-10; serrated side pins.
ASSA Twin 2; double spool "barrel" driver pin.
ASSA Twin Combi; graduated and double spool driver pins.
A Miracle Magnetic spool pin.
MIWA 3800 security pins.
Scorpion CX-5 security pins.
Hi-Shear LK1200 security pins.