Caring for your Locks
As frequently as locks are used, most receive little or no maintenance. For some reason, many people seem to believe a lock should work forever without any care. Frequently we hear, "The lock is as old as the house and we've never had trouble before." Without a little care, locks are bound to fail. Locks are machines, and like any other machine, require a little maintenance.
At the very least, the cylinders should be lubricated at least once a year, but not with just any lubricant. Do not use lubricants containing petroleum products or petroleum distillates. These oily lubricants attract and hold dust, dirt, and metal shavings; causing the problems you are trying to prevent. Additionally, they may react with both external and internal rust preventative finishes of the lock, defeating the rust preventative feature and creating a gum-like substance that will interfere with the proper operation of the lock.
Graphite is an old favorite for lubricating the lock cylinder. Graphite is effective but can be messy. The easiest lubricants to use are those with teflon or other formulations that lubricate and protect while dry. Look for lubricants specifically made for locks. Many "dry" firearm lubricants work well also. These products usually come with a straw that allows you to spray the lubricant neatly into the keyhole. Then work the key in and out of the lock, working the lubricant up into the pins and pulling debris from the lock. Wipe the key off when you pull it out of the cylinder to remove any dirt or debris that comes out of the cylinder. Make sure the key is coming out clean before turning the key in the cylinder.
Speaking of keys, the best practice is to set aside an original key to make duplicates from. Original keys are cut to exact tolerances. Duplicates will usually vary slightly from the original. Making duplicates from duplicates multiplies that variance and you may soon have a key that will not operate the lock. Keys are meant to wear before the pins in the lock, so if your key is showing signs of wear, replace it with a new duplicate of the original.
If the key enters and turns the cylinder smoothly, but the bolt or latch does not move freely (test operation with the door open), you may need to lubricate the latch, bolt, or concealed parts of the lock. For this, you will need to at least partially remove the lock from the door. Standard cylindrical locks and deadbolts are usually mounted with a couple screws on the interior side of the lock. Removing the lock will expose the latch or bolt. The dry lubricants work well here too, but larger moving parts can also be lubricated with lithium grease, which is also available in spray cans with straws. This will often rejuvenate a stiff latch or bolt.
When reassembling the lock on the door, test it with the door open before fully tightening the mounting screws. Many times there will be a bit of movement of the whole lock assembly in the door. Move the lock around and test for best operation before tightening the mounting screws.
Occasionally we are asked about cleaning the exterior surfaces of the lock. Care varies by manufacturer. Most locks have a clear coat finish, so no harsh or abrasive cleaners should ever be used. Some manufacturers suggest a mild dish detergent while others recommend water only.
We usually suggest lubricating the locks at least once a year, especially before harsh or freezing weather sets in. With a little care, you can greatly extend the useful life of your locks.