First, all locks need to be lubricated regularly in order to function correctly. I just got my lock 2 days ago and it is quite gritty when I first got it. Adding some lube make things all better. Here are 2 ways to lube:
A.) Run a pencil on the teeth of the key then stick the key into the lock. The graphite from the pencil will serve as a dry lube. Do that a few times.
B.) Use a waxed-based lube such as DuPont MultiUse Lubricant which is available at Wal-Mart and Lowes. They work well as chain lube as well. And the picture below shows it's dry once the carrier liquid evaporates:
Understanding the post I was responding was about a chain lock, but the lock mechanism are compatible.
Use in the demonstration are the extreme spectrum of Kryptonite locks. One is a $20 Wal-Mart variety that I use around campus for it has a longer shank. The other is top of the line $60 kryptonite fahgettaboudit mini.
Normally, all the plates in the locks should be aligned so the key can go all the way down.
However, under some usage condition such as rotating the key while removing it can cause the plates to misalign. And interestingly, the cheap locks have more plates to misalign than the fahgettaboudit:
Cheap (3 plates misaligned possible):
Fahgettaboudit (1 plate misaligned possible):
A.) Lube the lock well
B.) Make sure you do not rotate the key when you are inserting or removing the key from the lock.
C.) Do not turn the key until it's all the way in.
D.) If the plates are misaligned, you can use your key to re-align them. It's not difficult. You can play around it with your lock by purposefully mis-align the plates first, then realign them.
Hope this helps.