Cobalt Drill Bit 1/2 in Twist Drill Bits Pack of 5 - M35 High Speed

In this review the Cobalt Drill Bit 1/2 in set is assessed for machinists, metalworkers and serious DIYers who need a durable bit that cuts harder steels. The bottom line: these are practical, industry-grade M35 bits that deliver sharp, reliable drilling on stainless steel, cast iron and other hard metals thanks to a 135 split point and a fully ground flute design. The included index storage case keeps the set organized, and while durability reports are mixed, the overall value and cutting performance make them worth considering for heavy-duty work.

Key Features

• 1/2 in size, 5 pieces: A full set of five 1/2 in jobber length bits fits most power drills and covers common drilling needs without frequently swapping sizes.
• M35 cobalt construction: Industry grade M35 high speed steel with 5% cobalt offers increased hardness and wear resistance for drilling tougher materials.
• 135 degree split point: The split point reduces walking at startup so holes start accurately without a center punch in many applications.
• Fully ground spiral flute: Precisely ground flutes clear chips faster and reduce heat and friction for steadier cuts and longer edge life.
• Index storage case: A compact case keeps bits organized and protected between jobs, making transport and storage easier.
• Versatile material use: Designed for stainless steel, hardened steel (below HRC38), cast iron and softer metals and plastics when drilling speed and pressure are managed.

Who It's For

These bits are best for hobby machinists, metal fabricators and contractors who frequently drill through stainless steel, mild steel, cast iron or similar hard metals and want a reliable, sharper edge than standard HSS bits. The set is also practical for vehicle repair and maintenance where tougher alloys appear.

Casual DIYers who only drill wood or soft plastics might be better served by standard HSS or brad point bits that are lower cost. Also, users regularly working on extremely hardened steels above HRC38 should choose tooling rated for higher hardness instead of this M35 set.

Pros & Cons

Pros

• Excellent cutting sharpness and accuracy with a 135 split point that reduces walking.
• Greater hardness and wear resistance from 5% cobalt M35 material compared with ordinary HSS bits.
• Well-ground flutes that help chip evacuation and reduce heat buildup during drilling.
• Convenient index storage case for organization and protection.

Cons

• Some customers report mixed durability under heavy industrial use, so edge life may vary by application and technique.
• Not intended for steels hardened above HRC38, which require specialized tooling.

Specifications

Bit size	1/2 in
Quantity	5 pcs
Material	M35 high speed steel with 5% cobalt
Tip angle	135 degree split point
Shank	Straight shank, jobber length
Included accessory	Index storage case
Recommended materials	Stainless steel, cast iron, mild steel, aluminum, plastic, wood

Our Verdict

The Cobalt Drill Bit 1/2 in pack is a solid choice for anyone who regularly drills tougher metals and needs sharper, longer-lasting bits than standard HSS provides. With M35 construction, a 135 split point and a storage case, it balances cutting performance and value, though users drilling very hardened steels should select specialty tooling. Overall it is a practical, cost-effective set for metalwork and heavier DIY jobs.

Frequently Asked Questions

Can these bits drill stainless steel?
Yes, they are designed for stainless steel and perform well when drilling at appropriate speeds with controlled pressure to avoid overheating.

Are these suitable for very hardened steel?
No, the manufacturer notes hardened steel must be below HRC38; harder steels require purpose-made carbide or specialized bits.

Does the case keep bits organized for jobsite use?
Yes, the included index storage case stores the five bits securely for transport and prevents damage between uses.