https://writeablog.net/chordjudge35/the-three-greatest-moments-in-van-hook-lock-history Types of Deadlocks for Doors Hook bolt deadlocks are used on aluminum sliding narrow stile storefront doors to maximize security and strength of the lock. These locks are double-keyed to give greater flexibility in access control. To accurately measure for the new lock, first determine the door's case depth (or backset). This is the distance between the edge of the front door and the centre of the latch hole. Tubular Latch The tubular latch is the most well-known type of door latch. It's simple and straightforward to install, which makes it a favorite of DIY enthusiasts and joiners alike. It is available in various sizes shapes, shapes, and levels that can be used to match any door handle style. A tubular latch features a rectangular steel casing that has a spring-loaded followinger and a latch bolt (also called a striker). When you open the door the latch retracts to allow you to lock and close the door. When you close the door, the latch bolt springs back and grabs the edge of the frame to hold the door shut. When you're fitting a tubular latch, you'll have to determine the height at which you want the latch to be positioned on the door. Many people believe that a latch and handle should be positioned at a height of one metre above the floor. But this isn't always the case. The latch on the door knob should be placed in the middle of the rail. This is where the bulk of the weight is carried by the door when it is opened and closed. Once you've decided where the latch will sit and where it will be, mark the location of the hole on the door and strike plate using a pencil. Drill pilot holes to secure the plate. When you've drilled these then, use a countersink to ensure that the back of the plate sits flush with the door when it's screwed into place. If you are looking for a more robust alternative to the standard tubular latch, you should consider opting for a double-sprung mode