Cobalt Heavy Duty Drill Bit Pack of 12 - High-Heat Jobber Bits

Our review of the Drill America D/ACO series finds this pack of 12 cobalt jobber drill bits best suited for mechanics, metalworkers and serious DIYers who need durable bits for tough alloys. The single biggest reason to buy is their heat-resistant cobalt steel construction, which sustains higher cutting speeds and stays sharper when drilling stainless steel, nickel alloys and other high tensile materials. These bits are built to an aerospace standard and deliver clean, repeatable holes where standard HSS bits struggle.

Key Features

• Cobalt steel: Provides improved red hardness for higher cutting speeds and longer life when cutting hard metals such as stainless and inconel.
• Gold oxide finish: A thinner oxide layer that identifies the bits and offers corrosion resistance without affecting cutting performance.
• Round shank: Fits a wide variety of chucks and toolholding systems for flexible use across drills and drill presses.
• Right-hand spiral flutes: Evacuate chips up and out of the hole to reduce clogging and improve hole quality in through-drilling operations.
• 118 degree point: A standard point geometry that helps locate holes and works well for general purpose drilling in metal.
• Manufactured to NAS 907: Built to a recognized aerospace standard for consistent dimensions and performance.

Who It's For

This set is ideal for professional tradespeople and hobbyists who frequently drill stainless steel, titanium, PH stainless, and other hard alloys where cobalt drill performance matters. Users who value longer tool life and the ability to run drills at higher speeds will get the most benefit from this pack.

These bits are less necessary for occasional woodworkers or light duty home use where standard high-speed steel bits perform adequately; if you only drill soft materials infrequently, a standard HSS set will be more economical.

Pros & Cons

Pros

• Excellent durability and longer life on hard metals compared with standard HSS bits.
• Consistent, sharp performance that produces clean cuts and accurate holes.
• Standard 118 degree point and round shank make them versatile in many holders and tools.
• Manufactured to aerospace standard for reliable dimensions and quality.

Cons

• The gold oxide surface is thin and primarily cosmetic, so users seeking coated performance may find it similar to uncoated bits.
• Higher initial cost than general purpose HSS sets, though offset by longer life on tough metals.

Specifications

Our Verdict

These Drill America cobalt jobber bits are a practical choice for anyone who drills hard alloys regularly; they offer measurable durability and maintain sharpness under heavy use. For professionals and serious hobbyists working with stainless, titanium or nickel alloys, this 12-piece pack represents good value because the higher upfront cost is offset by longer life and higher workable speeds.

Frequently Asked Questions

Are these bits suitable for stainless steel?
Yes, the cobalt steel construction and higher red hardness make them well suited for stainless and other tough metals.

Do they require special holders?
No, the round shank is compatible with a wide variety of chucks and toolholding systems.

Is the gold oxide a performance coating?
Gold oxide is a thin surface treatment for identification and mild corrosion resistance; cutting performance is similar to uncoated cobalt bits.