M35 Cobalt Step Drill Set 1/4in - 1-3/8in (19 Step Size) - Stable

In this review the M35 Cobalt Step Drill Set is presented as a purpose-built option for DIYers and professionals who need reliable hole enlargement across metal and softer materials. The single biggest reason to buy is its M35 cobalt construction combined with a four groove spiral flute design, which yields improved stability and longer life when cutting through stainless steel, aluminum, wood and plastic. The reviewer found it especially useful when drilling multiple hole sizes quickly without swapping bits and praised its sharpness and cutting speed.

Key Features

• M35 cobalt high speed steel: Provides higher hardness, red hardness and wear resistance so the bit holds an edge longer on hard materials.
• Four spiral flute step design: Reduces flex during cutting and improves stability for cleaner, more accurate holes compared with ordinary step drills.
• Wide stepped range: Covers 1/4in to 1-3/8in across 19 steps so one bit replaces multiple individual sizes for faster workflow.
• TiAlN coating: Adds surface hardness and thermal resistance to lower friction and help maintain cutting performance at higher temperatures.
• 135 degree tip angle: The steeper tip is better suited to hard materials than a standard 118 degree point and helps start holes more precisely.
• Recommended cooling: Using cutting oil or water spray during continuous work reduces temperature and extends service life.

Who It's For

The set is ideal for DIYers, metal fabricators and maintenance technicians who frequently drill a range of hole sizes in thin to medium sheet metals, including stainless steel, and who value a single versatile tool over keeping many individual bits. The design suits projects where speed and repeatable accuracy matter, such as electrical panel work, bracket fabrication and retrofit installations.

Those who should look elsewhere include people who need extremely large diameter holes beyond 1-3/8in or those who primarily drill deep, solid stock rather than thin sheets, since step drills are optimized for sheet work and through-hole enlargement rather than deep plunge drilling.

Pros & Cons

Pros

• Durable M35 cobalt construction delivers longer tool life and better performance on hard metals.
• Four groove spiral flute design improves stability and cutting speed for cleaner holes.
• TiAlN coating and 135 degree tip reduce heat and improve starting accuracy on stainless steel.
• One bit covers 19 step sizes, saving time and tool changes on mixed-material jobs.

Cons

• Requires cutting oil or water spray for continuous high-speed use to prevent overheating and extend life.
• Step drills are not ideal for deep hole drilling or very large diameter cores beyond the listed range.

Specifications

Bit material	M35 cobalt high speed steel
Coating	TiAlN
Tip angle	135 degree
Size range	1/4in to 1-3/8in (19 steps)
Flute design	Four spiral flute step drill
Best for	Stainless steel, aluminum, wood, plastic

Our Verdict

The M35 Cobalt Step Drill Set is a practical, high-value tool for anyone who needs quick, accurate stepped holes across sheet metals and mixed materials. Its M35 cobalt body, TiAlN coating and four flute geometry combine to offer improved durability, cutting speed and hole quality, making it a smart single-bit solution for many shop and field tasks.

Frequently Asked Questions

Can this drill bit handle stainless steel?
Yes, the M35 cobalt steel and TiAlN coating are specifically suited to stainless steel and other hard materials when used with proper cooling.

Do I need lubricant when using this step drill?
For continuous or high-speed drilling it is recommended to apply cutting oil or spray water to reduce temperature and extend tool life.

What hole sizes does the bit cover?
The single bit covers stepped sizes from 1/4in up to 1-3/8in across 19 incremental steps.