How to Change Door Locks

Door locks help prevent unwanted visitors, thus providing protection for you and your family. These tips will teach you how to change a door lock properly so your home remains secure.

If, for security reasons, you want to change a cylinder lock (of which the night latch is the most common type) you need only replace the working parts. The same applies to mortise locks.

You will need:

• screwdrivers
• locking wrench
• pliers
• new cylinder and keys (for a night latch)
• junior hacksaw (if necessary)
• hammer
• new set of levers and keys (for a mortise).

Changing a cylinder lock

Be aware that you cannot change the cylinder on a night latch with a locking interior handle; this method works only for a simple night latch design.

1. Unscrew the lock cover on the inside of the door so that you can get at the screws that hold the cylinder in place.
2. Unscrew the cylinder and pull it out. The connecting bar will come with it.
3. Take your new cylinder; this too has a bar attached. The bar is divided into segments along its length. Hold the new connecting bar tightly in the locking wrench, and use the junior hacksaw to cut it to the same length as the old one.
4. Make sure that the new connecting screws are the right length. If they aren't, you'll have to trim them with the hacksaw. Insert the new cylinder into the hole. Tighten the screws, and then screw the cover back in place, making sure that the handle of the lock has slotted onto the bar.

Changing a mortise lock

Mortise locks come in various shapes and sizes. Take the old one with you when you go to buy a new one to avoid having to chisel out a larger slot in the door.

1. Unscrew the two screws that fix the cover plate and lock-face to the edge of the door. Turn the key so that the bolt shoots out, then remove the key.
2. Use a pair of pliers to grip the projecting bolt and slide the lock out of the door.
3. Put the new lock back in the slot, making sure it is inserted the correct way. Screw it and the cover plate in place, and make sure that the key turns smoothly.

Following these simple guidelines for changing a door lock will help keep your home secure.