Irwin 3/8″ x 4-1/8″ Left Cobalt HSS Fractional Drill Bit (30524)

Description

The Irwin 3/8″ x 4-1/8″ Left Cobalt HSS Fractional Drill Bit (30524) is a highly specialized tool designed for the removal of broken fasteners. Its primary benefit is its left-hand, or reverse, rotation which allows it to drill into a broken bolt or screw without tightening it. This action often grips the fastener and spins it out, eliminating the need for a separate extractor. Made with a premium 8% cobalt alloy, this drill bit provides superior heat resistance and durability when working with high alloy steels, stainless steel, and other hard materials. The mechanics-length design, which is shorter than a standard drill bit, offers increased strength and reduced risk of breakage. The 135° split point is self-centering and starts drilling on contact, minimizing “walking” and requiring less pressure.

KEY FEATURES AND BENEFITS:

• Left-hand rotation enables drilling into broken fasteners without tightening them further.
• 8% cobalt alloy construction ensures excellent heat resistance and long-lasting durability.
• Mechanics-length design provides extra rigidity and reduces breakage risk.
• 135° split point minimizes walking and allows for accurate starts with less pressure.
• Ideal for use on high alloy steels, stainless steel, and hard metals.

SPECIFICATIONS:

• Item Number: 30524
• Diameter: 3/8 inch
• Overall Length: 4-1/8 inches
• Flute Length: 2-3/8 inches
• Material: 8% Cobalt M42 High-Speed Steel (HSS)
• Point Angle: 135 degrees
• Hand Style: Left-Hand Cut
• Point Type: Split Point
• Finish: Gold Oxide
• Included in purchase: (1) Irwin 3/8″ x 4-1/8″ Left Cobalt HSS Fractional Drill Bit

HOW TO USE:

1. Preparation: Ensure the work piece is secure. If the broken fastener is protruding, use a center punch to create a divot in the center of the fastener’s head. If the fastener is flush or below the surface, this step is not necessary, as the split point will help center the bit.
2. Setup: Insert the Irwin 3/8″ Left-Hand Cobalt HSS Drill Bit into your drill. Set the drill to operate in reverse (counter-clockwise) mode. The left-hand rotation is essential for the bit to function as intended.
3. Drilling: Begin drilling slowly with light pressure. The split point will prevent the bit from walking. Allow the bit’s cutting action to work. As you drill, the left-hand rotation will attempt to unscrew the broken fastener.
4. Extraction: Continue drilling. In many cases, the drill bit will grab the fastener and spin it out on its own. If the fastener does not come out, the hole created is now ready to accept a screw extractor.

BENEFITS OF USING IRWIN 3/8″ X 4-1/8″ LEFT COBALT HSS FRACTIONAL DRILL BIT (30524):

• Reverse-cutting action: Removes broken fasteners without extra tools.
• High cobalt content: Increases performance and lifespan under tough conditions.
• Shorter mechanics length: Boosts rigidity and reduces breakage risk when drilling hard metals.
• Efficient solution: Saves time and eliminates the need for a separate extractor.

FEATURES:

• M42 high-speed steel with 8% cobalt: Offers excellent heat and wear resistance.
• Short mechanics-length body: Improves strength and stability while drilling.
• Spiral flute design: Helps eject chips quickly and cleanly.
• Left-hand cutting design: Suitable for counter-clockwise drill operation for extraction tasks.