The Spacesaver, first designed and patented by SDC, is a fundamental innovation in electric locking technology for access control applications. The stainless steel bolt projects at right angles to the lock mechanism, allowing installation of Spacesaver locks, by means of a simple cutout, in virtually any standard 1.75" frame, or in most door lock stiles. With the entire lock concealed, esthetic acceptability is complete, security is greater and installation in old or new construction is fast, easy and economical. Greater security is provided by the 0.625" diameter solid stainless steel bolt. The bolt rotates freely, making attempts to tamper or cut extremely difficult. The automatic relock switch keeps the bolt retracted while the door is open. The door depresses the ball switch assembly on closure, causing the bolt to project automatically, locking the door. In addition, the ball switch assembly is bidirectional, permitting the locks to be used on swinging and sliding doors. The auto relock assembly is field adjustable to compensate for wide door gap.