Cobalt Drill Bit Set 115Pcs M35 5% Cobalt - Hardened Metal Ready

In this review the Cobalt Drill Bit Set, 115Pcs, is examined for makers, machinists and serious DIYers who need a complete range of durable drill sizes for hardened metals and everyday materials. The bottom line: this set stands out for its breadth of sizes and the M35 5% cobalt construction, which provides reliable cutting on stainless steel, cast iron and other tough metals while still working well in wood and plastics. It is a practical worksite kit when you want long life from bits and a neat storage solution.

Key Features

• Comprehensive size range: The set includes 115 bits covering 1/16in to 1/2in in 1/64in fractional increments plus letter and numbered sizes, making it easy to match drill requirements without guessing.
• M35 5% cobalt alloy: The bits are made from high-speed steel alloyed with 5% cobalt for improved heat and wear resistance when drilling hardened metals.
• 135-degree split point: The pointed tip and twist design provide faster cutting and self-centering to reduce walk-off and improve hole accuracy.
• Durable construction: Fully ground twist jobber length design with a rigid, thick web core increases strength and reduces breakage under load.
• Bronze steam finish: Surface treatment improves hardness and toughness for wear resistance and lasting sharpness during repetitive use.
• Metal index storage box: The included metal storage box keeps all 115 bits organized and easy to identify on the bench or in a toolbox.

Who It's For

This set is ideal for metalworkers, maintenance technicians and serious hobbyists who regularly drill stainless steel, hardened steels, cast iron and a variety of softer materials. The broad size coverage and durable M35 composition make it a practical kit for jobs requiring multiple precise hole sizes without frequent bit changes.

Those who only need a handful of common sizes or who drill exclusively in masonry or ceramic should look elsewhere for specialized masonry or carbide bits, since this set is optimized for metals, wood and plastics rather than tile or concrete.

Pros & Cons

Pros

• Wide selection of 115 sizes eliminates the need to buy many individual bits separately.
• M35 5% cobalt alloy offers excellent wear resistance and better heat tolerance for hardened metal drilling.
• 135-degree point and fully ground finish deliver clean starts and accurate holes with less walking.
• Sturdy metal index box provides organized storage and fast size selection on the job.

Cons

• Not intended for masonry or tile, so separate carbide or masonry bits are required for those materials.
• High-quality cobalt bits can be more expensive to replace if lost, so organization in the box is important.

Specifications

Brand	Witwocky
Set size	115 Pcs
Material	M35 high-speed steel with 5% cobalt
Size range	Fractional 1/16in to 1/2in; Letter A to Z; Numbered #1 to #60
Point angle	135 degree split point
Finish	Bronze steam surface treatment
Storage	Metal index storage box

Our Verdict

The Cobalt Drill Bit Set 115Pcs is a strong choice for anyone who needs reliable drill performance across a very broad range of sizes, especially when working with stainless steel and hardened metals. Its M35 5% cobalt construction, fully ground tips and metal index box make it good value for workshops that value durability and organization, though users drilling masonry should choose a different specialist bit type.

Frequently Asked Questions

Are these bits suitable for stainless steel?
Yes. The M35 5% cobalt alloy and 135 degree point are designed for effective cutting in stainless steel and other hardened metals.

Does the set include metric sizes?
No. The set contains fractional inch sizes from 1/16in to 1/2in, letter sizes A to Z and numbered #1 to #60 as provided in the index.

Is storage included?
Yes. A metal index storage box is included to keep all 115 bits organized and easy to access.