A strike plate is a piece of hardware that works with a lock to keep a door secure. The strike is installed on the door frame and contains a hole that catches the latch or bolt that extends from the lock. The strike will hold the bolt in place, keeping the door locked until the bolt is retracted using a key or thumb turn. To allow proper clearance for the lock to operate, most strike plates are recessed into the door frame. If your frame does not have these recesses precut, you can create them yourself with some basic woodworking skills and tools.
Determine where to locate the strike plate by using the template supplied with your lock. If you do not have this template, coat the end of the bolt or latch with lipstick. Shut the door. Turn the key in the lock a few times so the bolt will protrude against the frame. When you open the door, you will see the lipstick mark where the bolt hits the frame.
Place the strike plate against the frame. Center the hole on the plate over the lipstick mark. Score around the edges of the plate with a utility knife. Trace the hole on the strike plate onto the door frame with a pencil. Mark the locations of screw holes with your pencil as well.
Predrill the screw holes at the locations you marked, using a bit one size smaller than the screw's diameter.
Cut a hole for the bolt, following the outline you traced, using a spade bit or hole saw. This hole will be slightly larger than the bolt, but should be no larger than the hole in the strike plate.
Chisel out the wood from inside the lines you scored with the utility knife. Strike the chisel with a hammer to carve away slivers of wood. Make the depth of the chiselled-out area the thickness of the strike plate, so the plate will sit flush with the surrounding surface of the frame. Keep testing the plate in the recessed area as you work, until you reach the correct depth.
Sand away any high spots within the recessed area that would cause the strike plate to be uneven. Sand the edges of the recess so they are smooth, to reduce the risk of splinters.
Close the door. Check that the bolt can extend fully into the holes you created. Enlarge the hole as needed until the bolt fits without catching. Fasten the strike plate in place, using a screwdriver and the screws that came with the plate.
The tolerance on doors and locks often is very small. If you install your strike plate and find that it is too far from the latch, try adding wooden shims behind the plate to bring it closer to the lock. If the plate is too close, try tightening the door's hinges to provide more clearance on the lock edge of the opening.