Drill America D Cobalt Drill Bit Pack of 12 - Jobber Length, Tough

In this review of the Drill America D Cobalt Drill Bit pack of 12 the bottom line is simple: these are jobber-length, heat-resistant cobalt drills built for cutting tougher metals where ordinary HSS will struggle. They are aimed at metalworkers, fabricators, and serious hobbyists who need bits that stay sharp when drilling stainless, high carbon steel, or nickel alloys. The reviewer found them notably durable and able to run at higher speeds than standard high-speed steel, making them a practical choice when working through thicker or higher tensile materials.

Key Features

• Cobalt steel construction: Provides higher red hardness so the bits tolerate higher cutting temperatures and maintain edge retention when drilling hard metals.
• Gold oxide finish: A thinner oxide surface treatment reduces visual wear without changing performance much, while making identification easier than bare bits.
• Round shank: Allows use in a wide variety of chucks and toolholding systems for straightforward setup and removal.
• Right-hand spiral flutes: Evacuate chips up and out of the hole to reduce clogging and help maintain drilling accuracy in deeper cuts.
• Manufactured to aerospace standard: Built to National Aerospace standard 907 for consistent geometry and material properties across the pack.

Who It's For

These drill bits suit machinists, metal fabricators, and home shop users who frequently drill stainless steel, high carbon steels, titanium or nickel alloys and need bits that can be run faster than conventional HSS. The set is useful for tasks such as through-holes in brackets, mounting holes in steel panels, and working with 16 and 18-gauge galvanized sheet where durability and sharpness matter.

Users who only drill soft materials like wood, plastic, or occasional mild steel and who prioritize coated finish for longer life in high-volume production may want a different specialty coating. Also, those who require tapered or non-jobber lengths should look at other specific bit families.

Pros & Cons

Pros

• Excellent durability and edge retention in hard metals compared with standard HSS bits.
• Allows higher cutting speeds - around 30 percent faster than HSS in many applications - so jobs complete quicker.
• Round shanks and standard jobber length make them versatile for common drill chucks and setups.
• Customers report good value for money and sustained sharpness through tougher tasks like 16 and 18-gauge galvanized steel.

Cons

• Geometry feedback is mixed among users, so a few may find the point or flute shape less than ideal for their specific technique.

Specifications

Brand	Drill America
Series	DWDCO
Material	Cobalt steel (heat resistant)
Finish	Gold oxide
Shank type	Round shank
Length style	Jobber length
Manufacturing standard	National Aerospace standard 907

Our Verdict

The Drill America D cobalt jobber set is a practical, cost-effective choice for anyone who drills harder metals regularly and needs bits that keep their edge and run at elevated speeds. For metalworkers and serious DIYers it delivers strong durability and usable performance for the price, though those seeking specialized geometry or non-jobber lengths should consider other options.

Frequently Asked Questions

Are these bits suitable for stainless steel?
Yes, the cobalt construction and higher red hardness make them effective for stainless and other high tensile alloys.

Will the gold oxide coating change drilling performance?
The gold oxide is mainly a thin surface treatment for identification; performance is similar to uncoated cobalt tools.

Can they be used in standard drill chucks?
Yes, the round shanks are compatible with common drill chucks and many toolholding systems.