Cobalt Drill Bit Set 21Pc M42 HSS Jobber Length - Durable Metal

In this review the COMOWARE 21pc Cobalt Drill Bit Set is evaluated for metalworkers and hobbyists who need a compact, versatile kit for hardened metals. The single biggest reason to consider this set is its use of 8% cobalt M42 high speed steel, which delivers noticeably better edge life and cutting through tough materials compared to standard HSS bits. For someone drilling stainless steel, cast iron or high temperature alloys, these bits offer a professional-grade option in a neat indexed case.

Key Features

• 8% Cobalt M42: Provides extended tool life and improved wear resistance when drilling hard metals compared to ordinary carbon or HSS bits.
• 135 split point: The precise split point reduces walking on the workpiece, so holes start cleanly without the need for a center punch in many cases.
• Fully ground twist design: Precision grinding ensures chips evacuate smoothly and cutting remains consistent during use.
• Gold oxide finish and straight shanks: The coating helps reduce friction while round straight shanks fit a wide variety of chucks and drill drivers.
• Jobber length set: The 21 sizes from 1/16in to 1/2in cover common shop and field needs without buying individual bits.

Who It's For

This set is aimed at tradespeople, fabricators and serious DIYers who frequently drill hardened metals such as stainless steel, cast iron and certain high temperature alloys, and who need a compact kit that travels to job sites. The M42 composition and split point make it appropriate for workshop tasks where longevity and clean starts matter.

Those who primarily drill softwood, plastics or occasional light metal may find a cheaper HSS set sufficient, and users who require metric sizes or extremely long bits for deep holes should look for a different kit tailored to those needs.

Pros & Cons

Pros

• High durability and heat resistance from 8% cobalt M42, making the bits suitable for stubborn metals.
• Reduced walking and cleaner hole starts thanks to the 135 split point geometry.
• Complete coverage of common fractional sizes in one indexed storage case simplifies organization and transport.
• Precision fully ground flute design helps chip clearance and cutting consistency.

Cons

• Some users report mixed durability under heavy industrial use, with occasional bits dulling or breaking sooner than expected.
• Set uses fractional sizes only, so metric users will need adapters or a different set.

Specifications

Our Verdict

The COMOWARE 21pc M42 cobalt jobber set is a solid value for anyone who regularly drills hardened metals and needs a compact, organized kit. It combines durable 8% cobalt construction with a 135 split point and thoughtful storage, making it a strong choice for workshop and jobsite use, while those needing metric sizes or ultra-high production longevity should evaluate specialized options.

Frequently Asked Questions

Can these bits drill stainless steel?
Yes, the M42 cobalt composition and split point are well suited to drilling stainless steel and other hard metals.

Are the sizes fractional or metric?
The set contains fractional sizes from 1/16in up to 1/2in; it does not include metric sizes.

Does the set include a storage case?
Yes, the bits come in an indexed plastic storage case for organized transport and protection.