Lock Science: Seasonal Lock Issues

      In Wisconsin, at some point the average temperatures change from cool days and chilly nights to below freezing most of the time; by deep winter, many people notice their locks and doors functioning differently. This happens because of the way temperature affects the materials inside of locks and doors. Let's look more closely at what's going on.

How Temperature Affects Lock Materials

Most locks today are made of metal parts; metal expands when it is warm and contracts when it's cold. The springs inside of a warm lock are more flexible and therefore it's easier for the key to activate the mechanisms inside. The springs inside of a cold lock, however, are contracted and stiff; the cold-contracted pins are fitting differently in their contracted housing- and therefore it becomes more difficult or even impossible to activate the lock and turn it. (This is the point when keys snap off in locks due to being forced while the lock is jammed.)

      “Sweating” can also occur when the temperature increases enough for moisture to condensate on the cold metal inside the lock (such as one that is exposed to morning sun after a cold night). When the temperature drops again (for instance, if the sun exposure ends later in the day), the condensed moisture that has accumulated on the metal freezes and can act as an obstruction to moving parts.

      This cycle of moisture condensing and refreezing along with the expansion and contraction of the metal will lead to rust and corrosion inside the lock. Standard oil-based lubricants that might have been working during the warmer seasons tend to pick up dust and thicken in the cold, causing the oil to gather up in dirty globs and prevent operation, and even leave parts of the lock without lubrication altogether. 

      Some results of all this temperature-related activity include jamming, misalignment, and even breakage on older parts that have been going through these changes for years. Here are some things you can do.

If your lock is sticking, Don’t force it!

Instead, try:

• Using a non-petroleum based lubricant designed for locks.

• Avoid using graphite- it's like adding dirt to the lock on purpose and jams locks the same way any other dust would. I CLEAN IT OUT OF LOCKS ALL THE TIME.

• Clean the lock with compressed air or a brush.

• Warm the lock with a dry source of heat, such as hand warmer

• pouches or a hairdryer. (Do not use water!)

• Use a lock cover to prevent moisture and dirt from getting inside the lock, and keep your keys clean.

• Try to keep the lock as dry as possible during the winter months.

      If even after all this DIY your lock is still sticking, it may be time to call a locksmith. I've completely disassembled locks, cleaned and lubricated every component, reassembled them, and had them work perfectly afterward- all they needed was a deep clean. The importance of regular maintenance can’t be overstated, especially when you live in a place like Milwaukee where temperature fluctuates so dramatically.