Step drill bit set (Ti-coated HSS with cobalt coating) — durable, precise, and easy to use. Key benefits Long-lasting hardness and performance: Made from high-speed steel (HSS) with a titanium (Ti) coating for exceptional hardness and sustained performance under frequent use. Smoother, cooler cuts: Cobalt coating reduces heat and friction for cleaner holes and longer tool life. Secure grip and stable drilling: Grooved (rill) design improves clamping, prevents slippage or drop-out during rotation, and keeps drilling accurate and steady. Broad material compatibility: Cuts clean holes in steel, brass, wood, and plastic, so you can use one set across many projects. Quick tool changes: Hex shank design provides a secure fit in standard drill chucks and quick-change bit holders, improving control and reducing wobble. How this solves common problems Eliminates wandering and tearing: The step profile and improved clamping produce cleaner hole edges and reduce the need for rework. Keeps cuts cooler and more efficient: The cobalt-treated cutting surface lowers heat build-up, which preserves bit geometry and reduces burning or melting on plastics. Reduces tool replacement frequency: Hard Ti-coated HSS withstands repeated use better than uncoated bits, saving time and cost. Typical applications Electrical and HVAC installation: Quickly enlarge or create clean conduit and knockout holes in sheet metal panels and junction boxes. Metal fabrication and repairs: Drill progressively sized holes in steel and brass for rivets, bolts, or threaded inserts without switching bits. Home improvement and DIY: Create neat holes in wood and plastic panels for fixtures, grommets, or cable pass-throughs. What to expect in use Reliable, precise hole-making across a range of common workshop materials. Secure mounting in hand drills and bit holders thanks to the hex shank. Fewer tool swaps and less rework due to durable coatings and stable clamping. Care and compatibility notes Use appropriate speed and cutting fluid for metal work to maximize life and performance. Compatible with drills and drivers that accept hex-shank bits and standard bit holders. This step drill bit set combines Ti-coated HSS strength, a cobalt cutting surface, and a grooved, hex-shank design to deliver dependable, versatile drilling for professional and DIY use.