Four Spiral Flute M35 Cobalt Step Drill Bit 1/4in-1-1/8in - Smooth

In this review the Four Spiral Flute M35 Cobalt Step Drill Bit stands out as a specialist tool for anyone who frequently drills a range of hole sizes in metal and mixed materials. The single biggest reason to consider this bit is its combination of an M35 cobalt body with a TiAlN coating and a four spiral flute geometry, which together deliver noticeably smoother cuts and fast feed rates when working on stainless steel, aluminum and other tougher substrates.

Key Features

• Four spiral flute: The unique four flute design reduces chatter and produces a smoother cutting action compared with standard double or triple flute step bits.
• TiAlN coating: A hard TiAlN surface layer increases surface hardness and helps resist wear, extending usable life under repeated metal drilling.
• M35 cobalt material: M35 alloy gives added toughness and heat resistance, making the bit more solid when cutting harder metals than conventional titanium bits.
• Wide size range: The stepped geometry covers 1/4in to 1-1/8in across 15 hole sizes, eliminating frequent bit changes for many sheet and panel tasks.
• Fast cutting feel: Customers report clean, burr-minimized holes and a sensation of cutting through thin metal like butter on aluminum and perf alum.

Who It's For

This step drill is well suited to HVAC techs, fabricators, maintenance staff and DIYers who need one versatile bit to punch multiple hole sizes in metal, wood and plastics. It is especially useful when working with stainless steel or aluminum where a standard step bit dulls quickly.

Those who work exclusively on very thin foil or delicate materials should test carefully, as there are mixed reports of breakage on the thinnest gauges and faster dulling under heavy continuous use; heavy production drill lines may prefer dedicated sheet-metal tooling or indexed step sets for continuous throughput.

Pros & Cons

Pros

• Four spiral flutes deliver smoother cuts and reduced vibration for cleaner holes.
• TiAlN coating and 89HRC surface hardness improve wear resistance for harder materials.
• M35 cobalt construction provides toughness and better heat tolerance than standard titanium bits.

Cons

• Some users report the bit dulls faster under very heavy use and can break on extremely thin foil, so it may not replace all dedicated production tooling.

Specifications

Our Verdict

The Four Spiral Flute M35 Cobalt Step Drill Bit is a strong value for technicians and serious DIYers who need a single, durable bit to cover many hole sizes in metal and mixed materials. Its four flute geometry, hard TiAlN surface and M35 construction produce cleaner holes and better wear resistance than many standard step bits, making it worth the choice for intermittent to moderate professional tasks.

Frequently Asked Questions

Can this bit drill stainless steel?
Yes; the M35 cobalt body and TiAlN coating make it suitable for stainless steel, though feed rate and cooling affect life.

What sizes are included?
The stepped bit covers 1/4in, 5/16in, 3/8in, 7/16in, 1/2in, 9/16in, 5/8in, 11/16in, 3/4in, 13/16in, 7/8in, 15/16in, 1in, 1-1/16in and 1-1/8in.

Is the shank compatible with quick-change holders?
The 1/4in hex shank fits most drill chucks and quick-change hex holders used in cordless and corded drills.