Cobalt Heavy Duty Jobber Drill Bit Pack of 12 - High Speed Performance

In this review the Drill America D/ACO75P12 pack is judged as a workman-grade set of cobalt jobber drill bits built for metalworkers who need reliable performance on hard alloys. The bottom line: these bits are for users who regularly drill stainless steel, nickel alloys or other high tensile materials and want bits that run hotter and last longer than typical HSS options. The set's cobalt construction and jobber length make it a practical choice for maintenance shops, fabrication work and serious DIYers who value durability and consistent hole quality.

Key Features

• Cobalt steel construction: Delivers higher red hardness so the bits tolerate higher cutting speeds and hold an edge longer when working stainless steel and nickel alloys.
• Gold oxide finish: Provides a thin surface treatment that resists light corrosion and helps visually identify the cobalt tools without changing cutting performance significantly.
• Round shanks: Fit a wide variety of chucks and toolholding systems for straightforward setup on handheld drills and drill presses.
• Right-hand spiral flute: Evacuates chips up and out of the hole to reduce clogging and help maintain cut quality in deeper holes.
• 118 degree standard point: Gives predictable centering and entry for general-purpose drilling across a range of metals.
• Manufactured to NAS 907: Produced to a recognized aerospace standard for consistent dimensions and quality.

Who It's For

These bits are aimed at professional tradespeople, shop technicians and serious hobbyists who need a dependable cobalt drill bit capable of cutting tough, heat-resistant alloys like PH stainless, Inconel and titanium. The pack format and jobber length suit repeat jobs where consistent bit life and predictable performance matter.

Users who only drill soft materials like wood or mild steel, or those who rarely drill metal, should consider less costly HSS or black oxide bits instead, since the cobalt grade is specifically beneficial when cutting harder metals and holding up under higher temperatures.

Pros & Cons

Pros

• Longer-lasting cutting edges on hard metals thanks to cobalt steel composition.
• Good value for a 12-piece pack compared with single-bit purchases, making replacements convenient.
• Consistent chip evacuation and cleaner holes due to the spiral flute design.
• Manufactured to an aerospace standard for reliable dimensions and repeatable performance.

Cons

• The gold oxide is mostly a cosmetic/thin treatment and does not offer the same lubrication or wear resistance as thicker coatings.
• Angle feedback from users is mixed, so very specific point geometries may vary slightly from expectations.

Specifications

Series	D/ACO Series
Material	Cobalt steel (heat resistant)
Pack quantity	12 bits
Point angle	118 degrees standard point
Shank style	Round shank
Surface treatment	Gold oxide thin finish
Manufacturing standard	National Aerospace Standard 907

Our Verdict

The Drill America D/ACO75P12 pack is a strong choice for anyone who frequently drills hard metals and needs durable bits that tolerate higher speeds. Its cobalt construction, consistent flute design and aerospace-level manufacturing make it good value for shop use where longer life and dependable holes matter.

Frequently Asked Questions

Are these bits suitable for stainless steel?
Yes. The cobalt steel construction is specifically effective for drilling stainless steel and other high tensile alloys.

Do they work in handheld drills?
Yes. The round shanks allow use in a wide variety of chucks on handheld drills and drill presses.

Is the gold oxide a wear-reducing coating?
The gold oxide is a thin surface treatment mainly for identification and light corrosion resistance; it does not perform like thicker lubricating coatings.