Padlock Parts and Mechanisms

Padlocks may look simple from the outside, but their internal parts work together in a precise way to keep your belongings secure. Understanding how a padlock is built helps you choose the right type for your application, compare security levels, and avoid common weaknesses.

Padlock Body

The body is the main solid part of the padlock. Most quality padlocks use brass, hardened steel, laminated steel, or alloy metals. The body protects the internal mechanism from force and drilling.
As padlocks get larger, the body can accommodate a more complex locking cylinder, increasing both strength and resistance to picking.
Disc padlocks are a notable exception because their bodies are formed from two metal casings that enclose the shackle rather than a single solid block.

Locking Cylinder And Keyway

Inside the body is the locking cylinder, which controls whether the shackle can open. Most keyed padlocks use a pin tumbler system.
The key enters the keyway and lifts a series of spring-loaded pins. When these pins align at the correct height, the cylinder is free to rotate, releasing the shackle.
The number of pins affects security:

• 3–4 pins: light to medium security

• 5–7 pins: higher security and more key variations
  More pins generally mean better protection against picking and higher “differ” counts (unique key combinations).

Shackle

The shackle is the U-shaped bar that loops around what you are securing. Because it is exposed, it is the most common target for cutting or leverage attacks.
Shackle materials vary:

• Hardened steel: high cutting resistance

• Boron alloy: very high resistance for high-security models

• Stainless steel: rust-resistant but slightly easier to cut

Some padlocks have spring-loaded shackles that pop open when unlocked, while others require manual lifting.

Security Trade-Offs By Design

Different padlock shapes change how the shackle is exposed:

• Closed shackle padlocks make the shackle harder to access with tools

• Straight shackle padlocks are designed for shutters and containers

• Disc padlocks offer natural closed-shackle protection due to their circular shape

• Long shackle padlocks offer more reach but lower cut resistance
  Choice depends on what you’re securing and the likely attack methods.