Things You'll Need
Fumbling through your key ring on a rainy night can be a nightmare when you have different keys to fit your front door, you side door, your back door and your garage. A simple but expensive option for making all your doors open with the same key is to pick up the phone and call a locksmith. But you might be able to save a lot of money by making a small investment in time. Any option you choose may require you to buy new doorknobs and locks, so make sure you take your locks to the store so they can tell you if all your current locks can be re-keyed to the same key.
Remove the Doorknobs and Deadbolts
Prop the door slightly open. Remove the two screws on the inside of the doorknob. Slide the exterior half of the doorknob off, while leaving the interior half of the doorknob in place. Use wire to secure this knob's key to the knob.
Repeat with all other doorknobs. Wire each key to its corresponding doorknob.
Remove the two screws on the inside of the deadbolts. Remove both halves of the deadbolt. Set the interior half aside. Wire each key to the exterior half of its corresponding deadbolt.
Re-key and Reinstall Locks
Take all of the knobs with their locks and keys to a home improvement store. Inquire whether they can be re-keyed to the same key and obtain a price for re-keying the locks. Compare that price with the price of buying new locks (not new knobs).
Have the old locks re-keyed, or buy new locks and have them re-keyed to the same key. Duplicate extra keys, as needed. Return home.
Insert the re-keyed doorknobs into the exterior side of the doors, carefully wriggling them into place while holding both halves of the doorknob. (Replace the interior half of the doorknobs with new ones only if you purchased new locks.) Replace the two interior screws. Repeat with the deadbolts and their mounting screws.
Most home improvement centers will re-key locks for free if they are purchased new from their store. You can leave the interior half of the doorknobs in the door when you are taking them apart because they easily stay in place. The deadbolts, on the other hand, want to fall out of the door, so you should set them aside. You don’t need to take the interior half of any of the locks to a home improvements store.