Porter-Cable 511 Cylindrical Lock Boring Jig. Features The quick easy way to install cylindrical locks Jig locates for 2 3/8" or 2 3/4" backset in seconds Adjustable for door thickness from 1 5/16" to 2 1/8 Drills all holes in one set-up Includes strike locator for accurate placement of jamb mortise Note: Spur bit shank design makes these bits interchangeable with Schlahe cylindrical lock boring system. Includes Cylindrical Lock Boring Jig - 511 1" boring bit 2 1/8" boring bit Full-up strike mortiser Latch mortiser Maximum security mortiser Strike locator Quik-Change drill adapter Storage Carrying case.