Heavy Duty Drill Bits — High-Speed Steel Options

Professionals typically use HSS drill bits with black oxide, TIN, or ALTIN coatings for metalworking and fabrication tasks. These bits offer reliable performance across jobber, screw machine, and taper length configurations, making them suitable for CNC machining, industrial production, and precision manufacturing environments.

For thick steel, heavy-duty HSS drill bits with a black oxide or ALTIN coating and a robust spiral flute design are recommended. Taper length or taper shank variants provide added reach and stability for deep-hole drilling, while the 118° point angle ensures efficient penetration into dense steel stock.

Hardened steel requires HSS bits with premium coatings like ALTIN (Aluminum Titanium Nitride), which offer superior heat resistance and hardness retention. Slower speeds, adequate lubrication, and a heavy-duty construction with reinforced flutes help maintain cutting edge integrity when drilling hardened materials.

Jobber Length bits are general-purpose with standard flute and overall length, suitable for most drilling tasks. Screw Machine Length bits are shorter and more rigid, designed for CNC and screw machine operations requiring greater stability and precision, and often conform to NAS Type C specifications.

ALTIN (Aluminum Titanium Nitride) coating is ideal for stainless steel due to its high heat resistance and hardness, which reduces friction and extends tool life. TIN coating is also effective for moderate-duty stainless applications, while black oxide suits general-purpose use on softer metals.

DI Tool's heavy-duty HSS drill bits are available in a comprehensive size range including fractional sizes from 1/16" to 11/16", numbered sizes #1 through #60, and lettered sizes A through Z, covering nearly all standard drilling requirements for metalworking and fabrication.