The independent keyed entry lock is separate from the door latch unit; to remove this lock is relatively simple. On the interior side of the door the lock unit has two (2) screws joining the interior portion to the exterior portion of the lock. Remove these screws and you will easily remove the lock unit from the door leaving only the dead bolt portion visible in the door. Now open the door and remove the two (2) screws in the bolt plate and slide the bolt from the door. This is the simplest installation/replacement as the holes are already drilled in position and all you have to do is exchange on lock of similar type with another. The only adjustments that may be needed it to drill ream the deadbolt hole a little larger to accommodate the new deadbolt portion of the new lock.
The door may not already have the holes drilled in it for a keyed lockset so this is the process to install your new lock. Packaged with the new lock is a paper template for the lock set. Locate where you want the lock and tape this template as instructed on the door, it should wrap three places, on each side of the door and the edge. You will find a center dot on the locations of the holes to be drilled at each place you can mark these with a scratch awl, if you do not have one an ice pick or even a finish nail will do the trick, just make a small hole through the dot on the template into the door proper. You will need a hole saw, (can be purchased at any home improvement or hardware store) this is a tool that is used with a power drill, it has a pilot drill and a cup-like saw blade. First from one side of the door, place the pilot drill against the small hole you just marked and drill into the door allowing the saw to cut half way through the door or just a little deeper. Remove the hole saw from the door by reversing the drill, if your drill does not have a reverse keep the saw running and pull back easily to remove from cut. Now go to the other side of the door and repeat the same motion you just did. At this point the block of wood in the center of the cut will be totally inserted into the hole saw and you now have a large hole for the lock. Please note: the size hole saw needed is on the instructions for the lock you bought, i.e.: 1 ½ or 2 inch diameter.
Now the next step is the edge of the door, you now have to drill the hole for the deadbolt. Using the size drill recommended (usually 1 inch) in the lockset instructions drill through the edge of the door, taking care that you do not split either face of the door as the wall will be quite thin. Holding the drill perfectly level continue through the lockset hole into the meat of the door an additional ¼ to ½ inch.
Assemble the lockset into the door, deadbolt first marking the deadbolt plate location with a pencil. Draw an outline of the plate on the door and remove the deadbolt unit. With a sharp utility knife cut the door edge along the pencil lines and then with a sharp chisel remove the wood inside those lines to the depth of the plate. REMINDER: USE EXTREME CARE, TOOLS ARE SHARP AND CAN CAUSE INJURY ALSO YOU DO NOT WANT TO SPLIT THE DOOR. Now completely install the all the lock components into the door and with door open check for smooth free movement of internal parts when turning key and that deadbolt extends out from door and returns flush to plate.
The final operation, take a grease pencil or lipstick and cover the face of the deadbolt and close the door and turn latch or key to press the deadbolt against the door frame. Withdraw the deadbolt and open door. You now have a grease pencil or lipstick mark on the casing where the hole needs to be drilled to accept the deadbolt receiver. After drilling the size hole to the depth stated in the instructions, place the receiver in the hole marking and mortising as you did with the deadbolt plate.
I you already have a combination door latch and deadbolt unit, measure the distance between the lock center and the center of the latch shaft and buy a new unit with the same measurement, these are fairly standard with maybe two or three different sizes. (Available at most home improvement or hardware stores) Then proceed to change lock units as described above with an existing lock.
Remember, you are using some power tools and sharp tools. Always wear eye protection and keep loose clothing, hair or other foreign objects away from moving parts.
