Why Is There a Small Hole in Padlocks? The Answer Might Surprise You

Have you noticed that most padlocks have a small hole in the bottom, and we're not talking about the keyhole. Here's why it's there!

You might have already come it across it several times without realising it. When holding a padlock, there is a tiny hole, usually on the underside. It's so small that neither a key, a screwdriver, nor even a toothpick could fit. You may be left wondering if it is part of the design, or if it serves an actual purpose? The answer is surprising.

This little hole serves several important functions for the proper operation of the lock, especially for models suited for outdoor use, meaning exposure to the elements.

First, the small opening allows water to drain out, particularly after rain. By providing an escape route for liquids, it ensures that the spring, which pushes up the shackle, doesn't rust, keeping the padlock functional. We often underestimate the impact of water on the lock's mechanism. Moisture can cause the internal components to rust and prevent the springs from moving, eventually jamming the lock.

Another major function of this hole is to regulate the effects of changes in temperature. Outdoor padlocks are often exposed to extreme weather conditions, from freezing winters to scorching summers. In cold weather, any moisture inside the lock could freeze and expand, potentially seizing up the mechanism. The drainage hole helps prevent this by allowing trapped moisture to escape, reducing the risk of the lock freezing shut. Similarly, in hot conditions, metal can expand. The hole provides some allowance for this expansion, preventing the lock from becoming stiff or difficult to open.

It is also simpler to maintain a lock with this feature. The tiny hole allows you to easily lubricate the internal components. A few drops of oil through the opening will coat the internal mechanism, keeping the springs and shackle in good working order. This regular upkeep, particularly in challenging weather environments, can significantly extend the life of the padlock. By lubricating the lock at least once a year, you can ensure it continues to function smoothly, avoiding rust and mechanical issues.