Sometimes the easiest way to make a key for a lock is to impression it. You take a key blank and wiggle it around and then look carefully for any indentations on the key blank. These marks you file down and repeat the process until the key turns. This allows you to replace lost keys for locks that either can’t be taken apart or might be difficult to take apart. Take this old Ford from the 60’s. Who knows what rusted out parts might not go back in under the dashboard if I took it off! It took only ten minutes to impression this key.