How to Install a Lockset
by Walter Curtis
Once you've hung a new door, you need to fit it with a lockset. 

What You'll Need
Here are the tools you'll want to have on hand to install a lockset:

Lockset 
Tape 
Pencil 
Power drill with hole-saw attachment 
Combination square 
Sandpaper 
Chisel 
Screwdriver 

Some doors come predrilled for standard-size locksets. Other doors require you to drill the holes yourself, using a template provided by the lock manufacturer. With any door, you need to cut mortises, or holes, in the door edge for the lockset and in the frame for the strike plate that engages the lock's bolt.

Here's how to install a lockset:

Step 1: Wrap the paper or cardboard template that comes with the new lockset around the edge of the door according to manufacturer's instructions. If necessary, use tape to secure the template. Template will be used to locate two holes: one hole for lock cylinder and the other for edge of door for bolt. Mark centers for these two holes on door.

Step 2: Use a power drill with hole-saw attachment to drill hole the size specified for lock cylinder. Be careful not to damage the veneer on the opposite side of door. When you see the point of the drill coming through, stop and finish boring from other side.

Install the outside lock cylinder so the stems or connecting bar 
fits into the bolt assembly.

Step 3: Drill a hole the appropriate size for the bolt into the edge of door until you reach the cylinder hole. Use the combination square against the edge of the door and the drill bit to keep the bit at a right angle to the door. Smooth edges of holes with sandpaper.

Step 4: Insert the bolt into the hole, and place the bolt plate in position over it. Trace the bolt plate's outline on the edge of door. Follow the manufacturer's instructions to remove the bolt and mortise edge for the bolt plate so it will be flush with the surface.

Step 5: Use a chisel to cut the mortise. Insert the bolt and plate in the mortise, and drill the pilot holes for mounting screws. Install the screws to secure the bolt in place.

Step 6: Insert the outside lock cylinder so the stems or connecting bar fits into the bolt assembly. Attach the interior lock cylinder, and secure it with the screws.

Insert the bolt assembly and trace its outline over the edge of the door. 
Remove excess wood to mount the assembly.

Step 7: Locate the proper spot for the strike plate on the jamb, and drill the proper-size hole in the jamb. Using the strike plate as a pattern, mark the jamb for mortising, and cut the mortise. Install the strike plate with screws so it fits flush with the jamb.