Our special 65° shoulder Sight Base Cutter designed to cut dovetails for both standard Colt factory and mil-spec 1911 Autos, and for replacement sights like Wichita Hi-Mount, older Bo- Mar and others with a 65° shoulder. Some makers use a 60° dovetail on their rear sights and we also have a cutter to match them. For low-mount adjustable sights use the Standard Sight Base Cutter shown on this page. Actual cutting diameter is .330' so more than one pass will be required to install most sights. This is done on purpose to allow for factory variations in base width as well as milling tolerances. CAUTION: For use in milling machine only. High speed steel, 2' (5cm) long, 3⁄8' (9.5mm) diameter shank. 60° or 65° shoulder. DO NOT EXCEED 700 rpm, HIGHER SPEED WILL BREAK TEETH.