IRWIN Drill Bit Set 63137 15 Piece 1/16 to 1/2 Inch M42 Cobalt Alloy Steel (135 Degree Split Point Jobber Length Hardened Metal Index Case Tool)

IRWIN 63137 15-Piece M-42 Cobalt Alloy Steel Jobber Length Drill Bit Set

The IRWIN 63137 15-Piece Cobalt Alloy Steel Drill Bit Set provides severe abrasion resistance and high heat dissipation for boring into hardened structural steel, cast iron, and 300/400-series stainless steel alloys. Manufactured from premium M-42 5% cobalt steel, each jobber length bit incorporates a 135-degree split-point tip that begins cutting instantly on contact without bit walking or center punching. Spanning fractional diameters from 1/16 inch to 1/2 inch in 1/32-inch steps, the heavy-duty spiral flutes extract dense metal chips rapidly to eliminate heat binding in production fabrication and machinery maintenance.

Best Used For:

• Stainless Steel & Alloy Machining: Penetrating heat-treated stainless sheet, titanium plate, and high-tensile fasteners without work-hardening the workpiece.
• Heavy Equipment Fabrication: Drilling through structural carbon steel beams, cast iron engine blocks, and weld seams using stationary and magnetic drill presses.
• Broken Fastener Extraction: Centering and drilling out sheared grade 8 bolts and hardened studs with immediate split-point bite.

Key Performance & Safety Features

• M-42 5% Cobalt Formulation: Premium alloy steel maintains cutting edge hardness under severe frictional temperatures that degrade standard high-speed steel.
• 135-Degree Split-Point Tip: Self-centering tip architecture bites immediately into curved and flat surfaces, eliminating walk and reducing feed force.
• Heavy-Duty Parabolic Web: Strengthens bit core geometry to resist torsional fracturing and chatter under heavy feed pressure.
• Reduced Cutting Lip Torque: Shortened cutting lips reduce rotational resistance for smoother cutting in tough tensile alloys.
• All-Steel Metal Index Case: Industrial hinged storage box protects cutting edges and arranges fractional sizes in labeled flip-up racks.

What's Included

• (15) M-42 Cobalt Alloy Steel Drill Bits: 1/16", 3/32", 1/8", 5/32", 3/16", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 13/32", 7/16", 15/32", and 1/2"
• (1) Heavy-Duty Metal Index Storage Case

Technical Specifications

Pro-Tip: When boring through work-hardening stainless steels, maintain steady downward feed pressure at reduced drill speeds and apply a sulfur-based cutting fluid; relieving feed pressure allows the bit to rub rather than cut, rapidly hardening the metal surface.