The No 7740 full mortise privacy lockset for knobs is based on an interior mortise lock design manufactured in New England in the early 20th century. It shares a common mortise size with other 7700 series locksets for ease of door preparation. The bevel of the faceplate is adjustable for thicker doors. A strike plate and wrought metal dustbox are provided. The lock features a 2-1/2″ backset and a 6″ x 1″ faceplate, which it shares with the interior passage latch set. The distance between the handle and the thumbturn is 3”. The bevel of the faceplate is adjustable for thicker doors. All Nanz plated and patinated finishes are available. The thumbturn spindle must be cut to extend no further than halfway through the thumbturn hub in order for the emergency release tool to retract the privacy bolt.