Storm / Security Door Mortise Lock Replacement Guide

Storm / Security Door Mortise Lock Replacement Guide

This is a guide to replacing the mortise lock in a security or storm door.

There are many different styles and brands of locks out there--many more than we've shown here. These are some popular brands of locks--some of them we carry in stock; others have been discontinued and we can no longer acquire them. Because the price of buying a new lock is typically less expensive than that of purchasing a whole new door, we've compiled a list of measurements you need to know to shop for a replacement lock.

Escutcheon plate screw hole spacing: The distance between the two screws securing the escutcheon plate to the face of the door

If the screw hole spacing is different on the replacement lock than on the original lock, you may need to drill new holes in the face of your door. If you cannot find a lock with the same screw spacing, try to find one with a larger screw hole spacing than your original lock so that the new escutcheon plate covers up the original screw holes.

Backset: The distance from the center of the cylinder to the edge of the door

If the backset is different on the replacement lock than on the original, you will have to enlarge the hole in the face of your door. Not only is this a lot of work, but you will likely also be able to see parts of the old hole when you install your new lock.

*Note: the standard backset of a security door mortise lock is 7/8 inch. We carry an adjustable lock that can replace locks with backsets of either 7/8 inch or 1 inch: # 302040

Faceplate screw hole spacing: The distance between the two screws securing the faceplate to the edge of the door

If the screw hole spacing is different on the replacement lock than on the original, you may need to drill new holes in the edge of your door. If you cannot find a lock with the same screw spacing, try to find one with a larger screw hole spacing than your original lock so that the new faceplate covers up the original screw holes.

Door thickness

A lock made for a different thickness than your door will not work. The spindle length and cylinder length will both be off and will affect the lock's performance. Handles may fall off or not secure firmly. The cylinder may jut out and keep the escutcheon plate from laying flush on the door.

To find a mortise lock for your storm / security door, click here.