How to Make an Antique Doorknob Work on a Modern Door

Remove the existing doorknob by unscrewing the screws on the knob plates. Most knobs have two screws on the plate. Pull the doorknob apart and slide it out of the hole.

Put the plastic doorknob adapter into the pre-drilled door hole so that it is centered vertically. Insert the passage latch through the hole on the side of the door and into the adapter.

Line the pegs on the doorknob rose so they slip into the holes on the adapter. One doorknob rose has two pegs, and the adapter has two vertical holes. Push the doorknob rose into the the adapter so it fits neatly into the holes.

Hold the other doorknob rose on the other side of the door and line up the two holes with the adapter's two holes. Insert a screw into the rose so it goes through the rose and into the holes in the adapter. Screw the top screw loosely in position to keep the rose in place.

Insert the doorknob with the wider shaft through the adapter. Feed the other door knob, with the narrower shaft, into the other shaft and screw them together. The two door knobs have threads so they are easily hand-screwed together.

Adjust the roses and door knobs so they fit the door perfectly. Tighten the screw on the side of the knob with a screwdriver or Allen key.

Turn the passage latch on the side of the door so it is angled to allow the door to open. It can face either left or right depending on which way the door will open. Secure it by screwing the keeper plate to the door.