Irwin 1877715 3/8″ High Speed Steel Black Oxide Countersink Drill Bit

The Irwin 1877715 3/8″ High Speed Steel Countersink Drill Bit is designed for producing clean, accurate countersunk holes for medium-size flat-head fasteners in a variety of machinable materials. Manufactured from industrial-grade high speed steel, this countersink delivers reliable cutting performance for metalworking, woodworking, and general fabrication tasks. The 3/8-inch diameter offers a balance between control and coverage, making it suitable for both shop and jobsite use.

This countersink features a precision ground 82-degree cutting angle, which matches the standard profile used for most flat-head screws in metal, wood, and plastic applications. A multi-flute cutting design helps reduce vibration and chatter, resulting in smoother cuts and improved accuracy. The black oxide finish adds corrosion resistance and reduces friction during cutting, supporting longer tool life. With a compact overall length and a standard 1/4-inch round shank, the Irwin 1877715 fits most handheld drills and drill presses for flexible use across multiple work environments.

Irwin 3/8″ High Speed Steel Black Oxide Countersink Drill Bit At a Glance

• 3/8″ Countersink Diameter: Ideal for common flat-head fastener sizes
• 82° Cutting Angle: Matches standard fastener profiles for flush seating
• High Speed Steel Construction: Provides durability and consistent cutting performance
• Multi-Flute Design: Reduces vibration for smoother operation
• Black Oxide Finish: Improves corrosion resistance and cutting efficiency
• 1/4″ Round Shank: Fits most drills and drill presses
• Precision Ground Cutting Edges: Delivers clean, repeatable countersinks

Markets

• Metal Fabrication and Assembly: Used for preparing fastener holes in steel and aluminum
• Woodworking and Carpentry: Suitable for countersinking screws in framing and finish work
• Automotive and Equipment Repair: Useful for brackets, panels, and hardware installation
• Maintenance and Facility Services: Supports daily repair tasks across mixed materials
• Manufacturing and Production: Helps ensure consistent fastener seating
• Trade Schools and Educational Programs: Ideal for teaching proper countersinking techniques

Proper countersinking is essential for fasteners to seat flush and assemblies to fit correctly. The Irwin 1877715 countersink drill bit is designed to deliver accurate results for medium-size fastening applications across metal, wood, and plastic. Its 82-degree cutting angle aligns with common flat-head screws, helping reduce rework and improve finished appearance.

The high speed steel construction provides dependable cutting performance, while the black oxide finish helps extend service life in shop and jobsite conditions. With a standard 1/4-inch shank, this countersink integrates easily with handheld drills and drill presses, making it a practical choice for fabricators, contractors, and maintenance crews who need reliable, repeatable countersinking results.

Irwin 1877715 3/8″ High Speed Steel Black Oxide Countersink Drill Bit Features

• Industrial-Grade High Speed Steel: Provides strength and wear resistance for repeated use
• Precision Ground 82° Tip: Designed for standard flat-head fastener applications
• Five-Flute Cutting Geometry: Reduces vibration and improves cut quality
• Black Oxide Coating: Helps resist corrosion and reduce friction during cutting
• Machinable Material Compatibility: Suitable for iron, steel, soft metals, plastics, and wood

Irwin 1877715 3/8″ High Speed Steel Black Oxide Countersink Drill Bit Includes

• (1) 3/8″ High Speed Steel Countersink Drill Bit

Irwin 1877715 3/8″ High Speed Steel Black Oxide Countersink Drill Bit Specifications

• Diameter: 3/8 in.
• Cutting Angle: 82 Degrees
• Shank Size: 1/4 in.
• Shank Type: Round
• Material: High Speed Steel
• Finish: Black Oxide

Why Customers Choose the Irwin 3/8″ High Speed Steel Black Oxide Countersink Drill Bit

Customers choose the Irwin 1877715 countersink drill bit because it delivers consistent, clean countersinks for common flat-head fastener sizes used in metalworking, woodworking, and maintenance applications. The high speed steel construction provides reliable cutting performance, while the black oxide finish helps protect against wear and corrosion in everyday use.

Its 82-degree cutting angle ensures proper fastener seating, reducing the need for secondary finishing. Combined with a standard 1/4-inch shank and a stable multi-flute design, this countersink is a dependable option for professionals and advanced DIY users who need accurate, repeatable results across a variety of materials.