While reliable, door locks are not completely maintenance-free. Since the average homeowner knows almost nothing about these devices, don't pay attention to them until problems arise.
Most of these issues don't require a licensed locksmith to visit, they need door & window lock repair specialists. A little information and a little bit of elbow grease are all it takes to solve the following key repair problem yourself.
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Adhesions and spasms
Even though you've kept your keys clean (and most of us haven't), wear and tear can build grit and dirt on your door locks. Over time, this buildup can impair basic function through attachment or spasm.
It's not locked
If you receive a new set of keys, they may not work as intended. The most common reason for this is because of the rough edges that need to be shaped. As a result, they were able to get into the lock but not turn the mechanism. An easy way to solve this problem is to go to a local locksmith.
If the latch doesn't click, there must be a problem with the firing pin, which is the flat metal plate on the door frame where the latch enters. Loose screws that the attacker could use to move around with ease usually caused problems. If you remove the plate, move it, and screw it back on, the bolts will work smoothly again.