How to drill hardened steel

• Glass and tile bits.   [1] [1-archive] [▶2]
• Masonry bits, which are typically carbide-tipped. You need to sharpen them with a diamond grinding wheel.   [▶1] [▶2] [▶3] [4]
• If using a hand-held drill, then use cobalt bits instead of carbide.
• Other drill bit options   [1]