A padlock may seem simple, but it’s one of the most dependable tools for protecting belongings — from bikes and sheds to toolboxes and gates. Built to handle weather and force, these locks also include a tiny feature most people overlook: the small hole at the bottom.
The Hidden Purpose of the Padlock Hole
That little hole serves a crucial function. Since padlocks are metal, they’re vulnerable to rust and moisture buildup. Rain, humidity, and temperature changes can cause water to collect inside, damaging the inner mechanism.

The bottom hole acts as a drainage point, allowing trapped water to escape. This helps prevent corrosion and keeps the lock working longer.
Why Some People Ignore It
Although the drainage hole was once a major innovation, many modern padlocks are now weatherproof and built to withstand year-round exposure. Still, classic padlocks with the hole remain popular because they’re strong, affordable, and easy to maintain.

A Second Purpose
The hole isn’t just for water. When a padlock becomes stiff or difficult to open, the opening allows you to spray lubricant directly into the mechanism. A quick application often frees up the moving parts and restores smooth use.
Hidden Features in Everyday Tools

Padlocks aren’t the only everyday objects with small details that serve big purposes. Many tools include useful design tricks people rarely notice.
Screwdrivers as Wrenches
Most screwdrivers can fit into a wrench opening, giving extra reach and leverage in tight or awkward spaces — a feature mechanics rely on often.