Cobalt Drill Bit Set 115 PCS M35 High Speed Steel - Versatile Kit

Our review of the Cobalt Drill Bit Set 115 PCS looks at whether this large M35 high speed steel collection is worth adding to a tradesperson's or hobbyist's toolbox. Bottom line: the set is best for users who frequently drill hardened metals and need a wide range of sizes, because the M35 (5% cobalt) material and the 135 split point are designed to resist heat and reduce walking for more accurate holes when cutting stainless steel, cast iron, titanium alloys and similar tough materials. It is not a miracle cure for every application, but it is a strong value for metalworking needs.

Key Features

• M35 High Speed Steel: The cobalt alloy delivers extended tool life and better wear resistance when drilling high tensile materials compared with ordinary HSS bits.
• 135 Split Point: The self-centering tip prevents walking so holes start precisely and drilling is faster with less pilot work.
• Fully Ground Twist: The ground flutes eject chips more efficiently, lower friction and help keep cutting temperatures down for longer bit life.
• Wide Size Range: The 115 piece mix covers fractional, letter and numbered sizes so you can match the bit to small precision holes or larger through-holes without guessing.
• Versatile Material Use: The set is tailored for hardened metals but also performs adequately in plastics and wood for general workshop use.

Who It's For

This set suits metalworkers, fabricators, automotive technicians and serious DIYers who regularly drill stainless steel, cast iron, high temperature alloys or titanium where a tougher HSS bit is needed. The comprehensive size assortment is useful for people who want to avoid buying individual bits for every job.

Those who primarily drill soft materials like softwood or occasional household tasks might find the set overkill and could save by choosing a smaller, cheaper kit designed for wood and general purpose use. Users who require industrial production life or very long-term toughness should compare to higher-end industrial brands.

Pros & Cons

Pros

• Good value and variety with 115 pieces covering fractional, letter and numbered sizes for flexible use.
• M35 cobalt alloy and fully ground twist design improve heat resistance and chip clearance for better metal cutting performance.
• 135 split point helps start holes cleanly and reduces the need for center punching on many materials.

Cons

• Customer feedback on durability and sharpness is mixed, so longevity may vary by use and technique.
• Some users report variability in steel quality across bits, which suggests inconsistent manufacturing tolerances in parts of the set.

Specifications

Material	M35 High Speed Steel (5% cobalt)
Tip Type	135 split point
Shank	Round straight shank
Twist Design	Fully ground twist flutes
Contents	115 pcs: 29 fractional (1/16 to 1/2 by 1/64 in), 26 letter sizes A to Z, 60 numbered gauges #1 to #60
Primary Uses	Hardened metal, stainless steel, cast iron, high temp alloy, titanium alloy, plastics, wood

Our Verdict

The Cobalt Drill Bit Set 115 PCS is a practical, cost-effective kit for anyone who needs a broad selection of bits capable of cutting hardened metals. Its M35 construction and split point design deliver real advantages when drilling tough materials, and the size range reduces the need for extra purchases. Buyers seeking maximum longevity or factory-grade consistency should weigh mixed durability reports, but for most metalworking hobbyists and mechanics this set represents solid value.

Frequently Asked Questions

Are these bits suitable for stainless steel?
Yes, the M35 cobalt steel and split point geometry are intended to handle stainless steel and other hard metals more effectively than ordinary HSS bits.

Does the set include both fractional and numbered sizes?
Yes, the kit includes 29 fractional sizes (1/16 to 1/2 in by 1/64 in), 26 letter sizes A to Z, and 60 numbered gauges #1 to #60.

Will these bits stay sharp a long time?
They offer improved wear resistance thanks to cobalt content, but customer reports on longevity are mixed and life will depend on material, speed and cutting technique.