General description Professional design ideal for drilling square holes in wood with a mortiser. The square hole drill bit is mainly used in the woodworking field, perfect for the construction, renovation, and decoration sectors. This set reduces the labor intensity of construction workers while accelerating work speed and reducing costs. Technical specifications Material: High speed steel Heat treatment: HRC48~50 Sizes: 1/4" (6.35mm), 5/16" (7.94mm), 3/8" (9.5mm), 1/2" (12.7mm) Compatibility and accessories Fits all machines and drill attachments Installation The punch square needs to use a drill, hammer, or other tools (none of these are included)