How to Convert a Cylindrical to Lock to a Mortise

Convert the Door Cutout

• 1

  Remove the old cylinder lock. Tape the template for the mortise lock on the door surface being sure to locate it in the best position to cover all existing holes. Trace the location of the cutouts, holes and mortises required for the new lock.

• 2

  Choose a bit the width of the end cutout of the mortise body and place it in the drill. Drill a series of vertical holes to remove the excess material needed for the mortise pocket depth and height specified on the template.

• 3

  Use a sharp chisel to remove the remainder of the material left by the drill and to smooth out the inside edges of the mortise pocket. Test fit the mortise in the cutout and adjust the hole as needed.

• 4

  Use a utility knife to trace the size and shape of the mortise finish plate on the edge of the door. Use the chisel to deepen the knife mark to the same thickness as the finish end plate. Carefully use the chisel to remove the material inside this cut to the required depth. This cut creates the shoulder around the mortise which holds the mortise in place. Test the mortise lock in the hole again, observing the fit of the face plate on the end of the door. When fully inserted in the mortise, the surface of the plate should be flush with the edge of the door. Make incremental adjustments in your woodwork until the proper fit is achieved.

• 5

  Drill any holes required for the handle installation in the face of the door. Pay close attention to holes that only penetrate from one side into the mortise pocket and do not go through the opposite side unless the template instructs you to do so.

• 6

  With all holes drilled and wood prepped, install the lock according to the instructions.