◆ Drill Size: #6, #8, #10, #12, #14
◆ Drill material: HSS
◆ Advantages: Make quick, accurate grooves in wood, metal and other materials. 1/4" shank and single flute are available for fitting quick change chuck. PATENT1: Both of the fasteners control the depth of the taper to keep the best appearance of screws, so it won't damage the drill bits. PATENT 2: The fastener locks against a chip to hold the drill bit tight completely.