Obviously, the ignition lock Ford uses in the Focus is a poor design. They know it, but for some reason Ford would rather irritate and drive away customers by continuing to produce vehicles with a known poorly designed part instead of admitting their mistake and taking action to really fix the problem. Taking your Focus to the local Ford dealer to get the ignition lock "fixed" only insures that, if you keep the car long enough, you'll get to take it back for them to "fix" it again. As of three months ago, the replacement ignition locks Ford was installing were the same fine pieces of junk they installed at the factory. Some people have changed their lock two or three times. Ford even added a new section to the later Focus shop manuals detailing how to drill out the lock for replacement when it can't be turned. If you want to fix the problem once, get a lock cylinder for a 2001 Explorer. It's part number 707592, made by Strattec. A good automotive locksmith will do the entire job for a lot cheaper than the Ford dealer. My locksmith didn't have any 707592 cylinders in stock when I needed one. He gave me the number of his wholesaler. Drove to the wholesaler's place and got the Strattec piece for $15. I then took that to the locksmith and he keyed it to match my original key for another $25. I installed it in about 25 minutes. There's a place in San Diego that will do the same thing if you email a pic of your key and then ship the new cylinder to you for under $100. Here's a link to them:
http://www.sandiegolockandsafe.com/