Double-cylinder deadbolts are recommended by law enforcement because they require that the deadbolt be locked or unlocked with a key from either side of the door and eliminate the interior turn latch that operate standard single-cylinder deadbolts. With regard to home security, this type of lock deters the opening of the door by breaking a nearby pane of glass. A double-cylinder deadbolt also prevents an intruder who has entered the home through a window from using the door to remove items from the home. Installation of a double-cylinder deadbolt uses the same size and dimension of pre-drilled door holes as a conventional single-cylinder deadbolt does, and it is installed using the same procedure.
Slide the throw bolt assembly into the pre-drilled hole in the edge of the door. Hold the faceplate flat against the door edge, positioned with equal vertical spacing on both sides to the door edge.
Draw an outline of the faceplate positioned in Step 1 on any wood surface overlapped by the faceplate.
Remove the throw bolt assembly from the door. Use a wood chisel or utility knife to remove any excess wood that is preventing the throw bolt faceplate from inserting flush with the door's edge surface.
Reinsert the throw bolt into the pre-drilled hole, pushing the faceplate flush with the door edge surface. Secure the faceplate to the door with the two screws provided.
Hold the exterior lock cylinder next to the door on the exterior side. Feed the tailpiece that extends from the internal surface of the cylinder through the tailpiece hole in the throw bolt arm visible in the door's cylinder hole. Press the deadbolt cylinder against the door surface. While keeping the cylinder pressed into position, insert the key--turning it to insure the throw bolt operates correctly and extends fully when the key is turned. If the throw bolt does not fully extend, remove the cylinder and rotate the tailpiece 180 degrees, then repeat this step until the throw bolt fully extends.
Position the interior deadbolt cylinder next to the door's interior cylinder hole, feeding the end of the tailpiece into the tailpiece slot in interior cylinder. Hold both cylinder sides against the door's interior and exterior surfaces. Insert the two machine bolts provided horizontally into the bolt holes in the interior cylinder and thread them into the exterior cylinder to secure them. Retest both sides of the lock with the key to make certain the throw bolt operates correctly and extends fully when the key is turned.
Retract the throw bolt and close the door.
Insert the key in the interior cylinder and extend the throw bolt to make certain the bolt extends fully and is centered in the strike hole in the jamb.
Center the frame reinforcer plate over the strike hole. Mark the jamb at any point where the inside edge of the reinforcer plate hole overlaps the wood. Use a wood chisel to remove any wood in the strike hole that obstructs the full insertion of the plastic throw bolt cup or the reinforcer plate and strike plate from sitting flush with the jamb surface.
Insert the plastic throw bolt cup in the strike hole. Place the reinforcer plate on top of it, then secure both in place with the provided 3-inch plated wood screws. These long wood screws secure the cup and reinforcer plate through the jamb and into the adjacent wall framing for maximum strength and security.
Attach the strike plate cover to the reinforcer place with the two provided small machine screws.