The MS® Prep is the industry standard lock prep and dominant locking solution for aluminum openings. The MS Prep is identified by the 6-7/8” x 1” cut-out with radius corners and is designed to fit Adams Rite MS deadlocks and deadlatches. Look for the MS® Prep symbol throughout this catalog to help identify these products.

When ordering and installing an Adams Rite lockset, here is some important information to keep in mind: 

Stile Prep & Mounting Methods

The stile prep indicates lockbody cutout and cylinder hole. 


Mounting Methods indicate how to mount the lockbody within the Prep.


Method A: 4104 Mounting Bridge: Method “A” spans the stile with a steel bridge at the top and bottom of the lock. A simple handle (Adams Rite Installation Tool 4075) is used to position the bridge accurately in the stile while its two screws are tightened to form a “web” in the door. Resilient washers allow for minor adjustment to fit the lock flush in the door.

Method B: 26-00090XX Tube Spacer: Method “B” requires two tapped holes in the back web of the stile and tubular spacers of appropriate lengths. Some door manufacturers use a heavy coil spring in place of the tube to allow for minor adjustment.

Method C: 91-0965 Kit for Radiused Door, 91-0966 Kit for Beveled Door: Method “C” was developed for use in Aluminum door jams for the purpose of retrofitting locks into existing doors. Its edge of the door location allows for easy application, reduces risk of door damage, particularly when used in glass doors, and makes drilling an easier process. It can also be used in metal or steel doors.

Lock Mounting Method for Hollow Metal Doors: Hollow metal doors with hardware preparation per ANSI standards have welded-in lock mounting tabs and require no modification to accept a lock manufactured with a mounting pattern conforming to these standards. (Examples: MS1850SN Deadlock and 4920AN Heavy Duty Deadlatch)

Lock Mounting Method for Wood Doors: A stepped mortise cutout is required in wood door installations. This mortise can be accomplished most easily with a router, but hand drill and chisel methods will suffice for single or low volume installations.

View Installation Instructions



It’s important to know the backset used on the stile as this will change the overall depth of the desired lock body. For example, if the backset on the opening is 1-1/8”, you will need to ensure that the desired lock body has a matching 1-1/8” backset in order to align properly with the prep on the door.

Backset is the measured distance from the centerline of the cylinder hole to the outside of the stile wall or nose. Use a tape measure or ruler to measure this horizontal dimension.