5/16" cobalt drill bit for hard metal - M35 cobalt drill bit by TTP HARD drills
DEWALT 5/8 in. Black and Gold Twist Drill Bit DW1622 G - The Home Depot
10-piece Metric Drill Bit Set, .5 - 5mm
Amazon.com: AConnet 3/16" - 5/8" Masonry Drill Bit Set, 9Pcs 3/8 Inch SDS Plus Bit Rotary Hammer Drill Bits Set Carbon Steel Carbide Tip Concrete Drill Bit Set for Brick, Stone, Block,