Four Spiral Flute M35 Step Drill Bit Set 1/4in - 1-1/8in (15 Sizes)

In this review the Four Spiral Flute M35 Step Drill Bit Set is presented as a solid choice for tradespeople and serious DIYers who need one bit that covers many hole sizes. The set's biggest selling point is its M35 cobalt construction and four spiral flute design, which combine to cut through stainless steel, aluminum, wood and plastic more smoothly and with longer life than ordinary step bits. For anyone who regularly drills thin sheet metal or wants to avoid swapping many twist bits, this set saves time while delivering consistent hole quality.

Key Features

• M35 cobalt steel: Provides higher wear resistance and pressure tolerance for longer life when drilling hard metals like stainless steel.
• Four spiral grooves: The four cutting blade design clears chips quickly for smoother cutting and faster drilling without clogging.
• TiAlN coating: Industrial grade coating increases hardness and heat resistance so bits stay sharper under heavy use.
• Wide size range: The single step bit covers 15 sizes from 1/4in to 1-1/8in so you can make multiple hole diameters without changing bits.
• 3/8in shank compatibility: The hexagonal shank fits common cordless drills and improves grip during high-torque drilling.

Who It's For

The set is ideal for metal fabricators, HVAC technicians, electricians and automotive hobbyists who need to punch a variety of hole sizes through thin sheet steel, aluminum and plastic without swapping bits. Its M35 cobalt composition and TiAlN coating make it especially useful when working with stainless steel where ordinary bits dull quickly.

It is less appropriate for users who frequently drill thick plate or require precision reamed holes; the step geometry is optimized for thin material and fast size changes rather than heavy stock removal or ultra-precise fit tolerances.

Pros & Cons

Pros

• Sharp, durable cutting edges due to M35 cobalt steel and TiAlN coating that resist wear.
• Faster, smoother cuts and better chip evacuation from the four spiral flute design.
• Convenient size range that replaces multiple individual bits and speeds workflow.

Cons

• Step bits are best for thinner materials; performance drops when used on very thick metal.
• Single-bit design limits use where extremely tight hole tolerances are required.

Specifications

Material	M35 cobalt high speed steel
Coating	TiAlN industrial coating
Shank	3/8in hexagonal
Size range	1/4in to 1-1/8in (15 sizes)
Cutting design	Four spiral flutes with four cutting blades
Compatible materials	Stainless steel, aluminum, wood, plastic
Warranty	Customer support with refund or replacement for broken hex shank

Our Verdict

The Four Spiral Flute M35 Step Drill Bit Set is a practical, long-lasting option for anyone who drills varied hole sizes in thin metals and plastic. Its M35 cobalt build and TiAlN coating deliver noticeably better wear resistance and cutting consistency than standard step bits, making it a good value for professionals and dedicated DIY users who want fewer tool changes and cleaner holes.

Frequently Asked Questions

Can these bits drill stainless steel?
Yes, the M35 cobalt composition and four flute design are suited to stainless steel when used with proper speed and lubrication.

What size range does one bit cover?
The step bit covers 15 incremental sizes from 1/4in up to 1-1/8in, allowing multiple hole diameters from a single tool.

Is the shank compatible with cordless drills?
Yes, the 3/8in hex shank fits most cordless drills and helps prevent slipping in the chuck.