Diablo Cobalt Pilot Drill Bit DHS4BITCB 4 Inch (1/4 Hex Shank 9/32 Diameter Snap Lock Plus Mandrel Stainless Steel Cast Iron Hardened Metals)

Diablo DHS4BITCB 4-Inch Cobalt Pilot Drill Bit for Hardened Metals

The Diablo DHS4BITCB is a 4-inch overall length by 9/32-inch diameter cobalt pilot drill bit engineered with a 1/4-inch hex shank for center-guided hole saw drilling through stainless steel, cast iron, and high-strength alloys. Formulated with heat-resistant cobalt alloy metallurgy that retains cutting edge sharpness under severe friction temperatures, this high-performance pilot bit integrates directly into Diablo Snap-Lock Plus mandrel systems. Designed for industrial fabricators, plumbers, and mechanical contractors using handheld drills or impact drivers, its precision web geometry prevents hole saw cup walking and bit slippage when penetrating hardened structural metals.

Best Used For:

• Stainless Steel Pipe & Plate Hole Saw Guidance: Establishing precise pilot holes through 304 and 316 stainless steel enclosures, structural tubing, and heavy plate stock without thermal dulling.
• Cast Iron Soil Pipe & Valve Box Drilling: Penetrating dense cast iron pipe walls and metal flanges cleanly to guide large-diameter hole saw cups.
• High-Strength Structural Alloy Framing: Drilling pilot centers through high-tensile structural steel beams, angle iron, and hardened metal enclosures.

Key Performance & Safety Features

• High-Heat Cobalt Alloy Formulation: Premium cobalt metal construction resists thermal degradation and edge wear during continuous dry drilling in tough alloys.
• Snap-Lock Plus Mandrel Compatibility: Connects seamlessly to Diablo quick-change mandrels for tool-free bit exchanges and instant hole saw cup mounting.
• Extended 4-Inch Deep-Reach Length: 101-6/10 mm total body length delivers proper pilot extension when paired with deep-cut hole saws.
• 9/32-Inch Precision Guide Diameter: Accurately dimensioned 0.28125-inch shaft stabilizes hole saw cups to eliminate rotational chatter and hole distortion.
• 1/4-Inch Anti-Slip Hex Shank Base: Universal 6.35 mm quick-change hex base locks securely into impact drivers and standard drill chucks without slipping.
• Rapid Chip-Evacuation Flute Architecture: Engineered flute geometry removes hard metal shavings quickly to reduce thermal buildup at the bit point.

What's Included

• (1) Diablo 4" Cobalt Pilot Drill Bit for Hardened Metals (DHS4BITCB)

Technical Specifications

Pro-Tip: Use low drill RPM and apply steady, continuous pressure with cutting fluid when drilling stainless steel to keep the cobalt tip cool and prevent work-hardening of the metal surface.