Unibit M35 Cobalt Step Drill Bit, 7/8"–1-3/8", 19-Step, TiAlN-Coated
Product description
The 7/8"–1-3/8" range and M35 cobalt high-speed steel make this step drill bit suited to creating graduated holes in sheet materials. Its 19-step profile brings multiple hole sizes into one bit, while four spiral flutes and a 135-degree cutting angle support a controlled approach to drilling.
Laser-etched markings help identify the step you need, and the storage case keeps the bit organized between jobs. For work that calls for several hole diameters, a stepped bit offers a different approach from carrying separate fixed-size bits.
The essentials
Made from M35 cobalt high-speed steel, this bit is designed for demanding drilling tasks in metal and other thin materials. The listed hardness is HRC 64–66, and the TiAlN coating adds surface hardness and resistance to high-temperature oxidation. These material features support use on steel, stainless steel, aluminum, and copper, as well as plastic and wood.
Four spiral flutes help carry chips away as the bit cuts, while the 135-degree cutting angle is designed to support chip removal and reduce wear. The result is a step-bit format for jobs where a range of hole sizes is more useful than a single fixed diameter. A 3/8" hex shank provides the connection point for a compatible drill.
Size & fit
The bit covers a stated cutting diameter range of 7/8" to 1-3/8" across 19 steps. Laser-etched size markings on each step make it easier to select the intended diameter during a project, whether you are preparing sheet metal for fittings or making openings in plastic. Match the 3/8" hex shank to your drill’s chuck before starting, and use the marked step as a guide for the target hole size.
Getting the most from it
This format is useful when a project involves more than one hole diameter in thin stock. For example, when preparing a metal panel with openings of different sizes, the stepped profile lets you work through the required diameters with one bit instead of switching among several fixed-size bits. Its four-flute design supports chip removal, and the markings help keep each opening aligned with the chosen step.
Use the bit for metal sheets, including steel, stainless steel, aluminum, and copper, as well as plastic and wood. Keep the bit organized in its storage case between jobs, this also makes it easier to bring along when working across different materials or hole sizes. You’ll appreciate it if your projects call for a clearly marked stepped bit with a broad stated diameter range and a 3/8" hex shank.
Questions before you buy
What materials can this step bit drill? It is intended for metal sheets, including steel, stainless steel, aluminum, and copper, along with plastic and wood.
How do I identify the hole size? Each step has a laser-etched size marking, so you can locate the diameter needed for the opening before drilling.
What is the size range and shank type? The cutting diameter range is 7/8" to 1-3/8", with 19 steps and a 3/8" hex shank.
Buying verdict
For sheet-material projects that call for several hole sizes, this M35 cobalt step bit combines a 19-step range, etched size markings, and four-flute geometry in one organized tool. It’s a practical fit for metal, plastic, or wood drilling where a graduated bit can serve a broader range of opening sizes than a single-diameter alternative.