This dial is equipped with double spline 5 ⁄16” - 40 spindles. A spindle is threaded and splined into a dial with its spline keyway aligned 19 on the dial. The #19 splining location is for right-hand constructed locks, which can be mounted RH, LH, VU, or VD. Dial spindles will accommodate a maximum door thickness of 3.4 inches (86.5 mm).