The Simpson 9/16 in. x 21 in. SDS-Max 2-Cutter Head Carbide Drill Bit is a premium, professional-grade rotary hammer bit engineered by Simpson for demanding concrete drilling, masonry, and demolition applications. The proprietary flute geometry reduces vibration and optimizes impact energy transfer from the rotary hammer into the drill bit tip, enhancing drilling speed and durability while reducing noise, stress, and vibration on the operator. Built on a chromium-nickel-molybdenum steel alloy body and finished with precision heat-treatment procedures, this bit is designed to deliver consistent, accurate performance through even the toughest reinforced concrete jobs.

Key Features

• Uniformly brazed carbide inserts - bond the cutting edges with consistent strength throughout the bit, resulting in longer bit life and fewer replacements on the job.
• Self-centering tips - guide the bit into position at the point of contact for accurate hole placement, reducing the chance of drift or misaligned anchor holes.
• Chromium-nickel-molybdenum steel alloy body - delivers the hammering quality and extended service life needed for heavy-duty structural drilling without premature fatigue or failure.
• Heat-treatment procedures and shot-peened finish - increase surface hardness and drilling speed, reduce drill bit wear, and improve resistance to bending forces so the bit holds up under sustained rotary hammer use.
• High-volume, multi-flute spiral - quickly channels concrete dust out of the hole during drilling, keeping the cutting zone clear to improve drilling speed and reduce overheating.
• 4 x 90 deg. head geometry - crushes through rebar and prevents the bit from sticking in reinforced concrete, keeping work moving on structural and commercial concrete applications.
• 2-cutter head design - provides aggressive material removal with each hammer rotation, making it well-suited for larger-diameter anchor and fastener holes in concrete and masonry.
• Conforms to ANSI Standard B212.15 - ensures the bit meets precise industry tolerance requirements, giving contractors confidence in dimensional accuracy and compatibility.
• SDS-max shank - locks securely into SDS-max rotary hammers for reliable torque transfer and tool-free bit changes, minimizing downtime between holes.

Why This Product

• Built for reinforced concrete without slowing down - the 4 x 90 deg. head geometry is specifically engineered to crush through rebar and resist sticking, so contractors can drill through structural concrete confidently without stopping to free a stuck bit.
• Reduced operator fatigue on long drilling runs - the proprietary flute geometry optimizes impact energy transfer and actively reduces vibration, noise, and stress transmitted back to the operator, making it a practical choice for extended drilling sessions.
• Longer service life through advanced metallurgy and surface treatment - the combination of a chromium-nickel-molybdenum steel alloy body, heat-treatment procedures, shot-peened finish, and uniformly brazed carbide inserts means this bit resists wear and bending forces far longer than standard concrete bits, lowering the cost per hole over time.
• Precision accuracy from the first contact - self-centering tips eliminate the need to pilot or guide the bit by hand, helping ensure anchor holes land exactly where structural plans require, which is critical for code-compliant fastener installation.

Specifications

• Model Number: MDMX05621
• Brand: Simpson Strong-Tie
• Shank Type: SDS-max Shank
• Head Type: 2-Cutter Head
• Diameter: 9/16 in.
• Overall Length: 21 in.
• Drilling Depth: 15-1/2 in.
• Material: Hardened Steel
• Country of Origin: Germany

Frequently Asked Questions

What type of rotary hammer is this drill bit compatible with?

This drill bit features an SDS-max shank, making it compatible with all current and older SDS-max rotary hammers from major manufacturers including Black & Decker, Bosch, DeWalt, Hitachi, Hilti, Kango, Makita, Metabo, and Milwaukee.

Can this drill bit be used in reinforced concrete containing rebar?

Yes. The 4 x 90 deg. head geometry is specifically designed to crush through rebar and prevent the bit from sticking in reinforced concrete, making it well-suited for demanding structural drilling tasks.

What is the actual usable drilling depth of this bit?

While the overall length of this bit is 21 in., the drilling depth is 15-1/2 in., which is the maximum depth you can drill into the material.

What quality standards does this drill bit meet?

This drill bit conforms to ANSI Standard B212.15, ensuring it meets precise industry tolerance requirements. The chromium-nickel-molybdenum steel alloy body, heat-treatment procedures, and shot-peened finish further ensure professional-grade performance and durability.

Note: Product dimensions may differ from picture. Please see the item description above for specifications.