The Simpson 7/8 in. x 21 in. SDS-Max Quad-Head Carbide Drill Bit is a premium-grade rotary hammer bit engineered for demanding concrete and reinforced concrete drilling applications. Built on a chromium-nickel-molybdenum steel alloy body with uniformly brazed carbide inserts, this bit delivers the speed, precision, and durability that professional contractors need when drilling anchor holes and structural attachment points in concrete substrates. The proprietary quad-head geometry and high-volume multi-flute spiral work together to maximize energy transfer, evacuate debris efficiently, and keep the bit cutting fast even through rebar-reinforced slabs.

Key Features

• Uniformly Brazed Carbide Inserts - Consistent brazing across all carbide cutting surfaces ensures even wear distribution, extending bit life compared to inconsistently bonded tips.
• Self-Centering Tips - The tip geometry registers accurately on the work surface before drilling begins, reducing walk-off and delivering more precise hole placement with less operator correction.
• Chromium-Nickel-Molybdenum Steel Alloy Body - This high-grade alloy composition maintains structural integrity under repeated hammer blows, supporting extended service life in heavy-duty rotary hammer use.
• Heat-Treatment and Shot-Peened Finish - Post-production heat-treatment and shot-peening increase surface hardness, improve drilling speed, reduce drill bit wear, and improve resistance to bending forces during aggressive drilling.
• 4 x 90 deg. Quad-Head Geometry - Four cutting edges arranged at 90 deg. intervals crush through rebar and prevent the bit from sticking in reinforced concrete, keeping work moving without costly interruptions.
• High-Volume Multi-Flute Spiral - The double-helix, high-volume flute design channels concrete dust rapidly out of the hole, reducing clogging and improving drilling speed in deep-bore applications.
• Patented Reinforced Core Flute - The reinforced core structure maximizes energy transfer from the rotary hammer into the drill bit tip, optimizing impact efficiency and reducing operator fatigue from vibration and noise.
• ANSI Standard B212.15 Compliance - Conformance to this recognized industry standard confirms that the bit meets established dimensional and performance benchmarks, supporting use on regulated job sites.

Why This Product

• Built to Cut Through Rebar Without Stalling - The 4 x 90 deg. quad-head carbide tip is specifically designed to crush through rebar encountered in reinforced concrete, making this bit a reliable choice for structural drilling where stopping to swap bits is not an option.
• Engineered for Speed and Reduced Fatigue - The combination of proprietary flute geometry, reinforced core, and optimized impact energy transfer reduces vibration and noise transmitted to the operator while maintaining fast drilling speeds, so crews can work longer with less physical strain.
• Long-Term Value Through Superior Materials - The chromium-nickel-molybdenum alloy body, uniformly brazed carbide inserts, and heat-treated shot-peened finish all work together to extend service life and reduce the frequency of bit replacement on high-volume drilling jobs.
• Precision Hole Placement from the First Strike - Self-centering tips allow the bit to register accurately on concrete surfaces immediately, minimizing layout errors and rework when hole position is critical for anchoring and structural attachment applications.

Specifications

• Model Number (MPN): MDMX08721Q
• Shank Type: SDS-max Shank
• Head Type: Quad Head - 4x Drill Bit
• Diameter: 7/8 in.
• Overall Length: 21 in.
• Drilling Depth: 17 in.
• Material: Hardened Steel with Carbide Tip
• Alloy Composition: Chromium-Nickel-Molybdenum Steel Alloy Body
• Standard Compliance: ANSI Standard B212.15
• Country of Origin: Germany
• Brand: Simpson Strong-Tie

Approved Applications

• Drilling into concrete, including reinforced concrete with rebar
• Heavy-duty rotary hammer drilling using SDS-max shank rotary hammers
• Applications requiring precise, self-centered hole placement
• Drilling and demolition tasks requiring high-speed concrete dust evacuation
• Professional construction, anchoring, and structural attachment applications in concrete substrates