Cobalt Drill Bit Set 20 Piece M35 3-Flute TiN Coated - Durable Metal

In this review the Cobalt Drill Bit Set 20 Piece is evaluated for metalworking and demanding workshop use; it is aimed at professionals and serious DIYers who need durable, precise bits for steel, hardened metal and cast iron. The single biggest reason to buy is the combination of M35 cobalt HSS with a TiN coating and a 3-flute geometry that together deliver longer life, faster penetration and improved chip evacuation compared with standard HSS bits.

Key Features

• M35 cobalt HSS: The 5% cobalt alloy increases heat resistance and longevity so bits hold an edge longer during tough metal drilling.
• TiN coating: The gold titanium nitride finish reduces friction and wear for improved durability and cooler operation under load.
• 3-flute design: Three cutting edges give faster penetration and smoother drilling while the extra flute improves chip removal and reduces clogging.
• 125 split point: The split point tip stays self-centering to minimize walking and produce cleaner, more accurate holes without excessive pilot work.
• Three-flat shank: Larger bits with 3-flat shanks mount securely in standard chucks to prevent spin-out and improve stability in both hand drills and drill presses.
• Indexed storage case: The durable indexed case keeps all 20 pieces organized and easy to select on the bench or in the toolbox.

Who It's For

The set is best for metalworkers, mechanics, and fabricators who regularly drill steel, hardened metals and cast iron and need bits that last longer than standard HSS. It also suits experienced DIY users who want a professional-grade kit for automotive, machinery or structural projects.

This is less suitable for users who only drill soft materials occasionally or who need metric sizing; hobbyists working primarily in wood or plastic will find more economical options. Also, note the 1/2 in bit is slightly shorter than standard lengths, which may matter for deep-hole work.

Pros & Cons

Pros

• Excellent durability from M35 cobalt HSS for extended tool life in hard metals.
• TiN coating reduces heat and friction for longer runs and improved wear resistance.
• 3-flute and 125 split point combination produces faster penetration and cleaner, self-centering holes.

Cons

• The 1/2 in drill bit is slightly shorter than typical long jobs may require, limiting deep-hole reach.

Specifications

Brand	OSTTE
Material	M35 cobalt high-speed steel (5% cobalt) with TiN coating
Flute types	3-flute (12 pieces) and 2-flute (8 pieces)
Tip geometry	125 split point for self-centering
Shank	3-flat shank on larger sizes to minimize spin-out
Set size	20 pieces in indexed storage case
Size range	1/16 in to 1/2 in

Our Verdict

This M35 Cobalt Drill Bit Set is a solid, value-forward choice for professionals and advanced DIYers who need robust bits for steel and hardened materials; its combination of cobalt HSS, TiN coating and 3-flute geometry delivers faster cutting, better chip control and longer life. Buy this set if you regularly drill metal and want fewer bit changes; if you only drill soft materials or need long-reach sizes, consider a specialized kit instead.

Frequently Asked Questions

Are these bits suitable for stainless steel?
Yes, the M35 cobalt HSS and TiN coating are intended for drilling stainless and other hardened steels, offering improved heat resistance and wear life.

Will the bits fit a standard drill chuck?
Yes, most bits use a round shank and larger sizes have a three-flat shank that fits securely in standard chucks to reduce spin-out.

Does the set include metric sizes?
No, the set is sized in fractional inches from 1/16 in to 1/2 in and does not include metric sizes.