When you have a new key cut, you should be able to take it home and use it straight away and have it work just as well as the old one. And, most of the time, that's exactly what happens. Unfortunately, though, it isn't always.
If you've got a new key and it's either not working properly or at all, it can be a pretty frustrating problem. In some cases, it can even leave you locked out, or stuck inside unable to secure your door.
If you're experiencing problems with a new key, here are some of the common causes, so you can narrow down what's going on and work out how to fix it.
The key is stiff
New keys quite often feel a bit stiff in the lock compared to the older one that's been used more. Usually, this will improve quickly after a few uses as the fine metal particles left after cutting get worn away, and the sharp edges of the new key soften. Try putting the key in and out of the lock repeatedly until it feels like it's working more easily. However, if it's particularly difficult to use and doesn't improve, it may be a more serious problem.
If you have another key available, compare it to check whether the problem is with the key or the lock. If it's the key, it could be that the cut isn't quite as precise as it should be, causing a bad fit. With keys, it only needs to be a tiny amount to make all the difference. In this instance, it's best to take it back to the key cutter for replacement.
It only works intermittently
When the key works sometimes but not always, it points to a very, very slight inaccuracy in the cut. While this could be an error on the part of the key cutter, it could also be because the key is several generations away from the original. When a key is cut, it can vary imperceptibly from the original, which is not normally a problem. However, if you're making a copy of a copy and so on down the line, these differences become magnified until they can sometimes stop the key from turning.
It doesn't work at all
Make sure the lock isn't the problem by trying a different key if possible. If it is the key, it's most likely a cutting error.
This could be caused by a number of things. The key cutter may have used the wrong base, which should be easy to see if the keys look quite different. Otherwise, it could be too far down the line of copies, as detailed in the explanation for intermittently-working keys. If you're stuck, you may have to get a locksmith to help you. Otherwise, take the key back to the cutter and get it replaced.