The Simpson MDMX08121Q 13/16 in. x 21 in. SDS-max Shank Quad-Head Drill Bit by Simpson Strong-Tie is a premium-quality, professional-grade carbide drill bit engineered for demanding rotary hammer drilling applications in concrete and reinforced concrete. Built with a proprietary quad-head dual-cutter design and high-volume double-helix flute geometry, this bit delivers exceptional drilling speed, superior durability, and reduced operator vibration - making it a top-tier choice for contractors and tradespeople tackling heavy-duty concrete drilling tasks.

Key Features

• Uniformly brazed carbide inserts resulting in longer bit life
• Self-centering tips for accurate hole placement
• Chromium-nickel-molybdenum steel alloy body ensures hammering quality and extended service life
• Heat-treatment procedures and shot-peened finish increase surface hardness, drilling speed, reduces drill bit wear and improves resistance to bending forces
• Drill bit conforms to ANSI Standard B212.15
• High-volume, multi-flute spiral quickly channels concrete dust from the hole to improve drilling speed
• 4 x 90 deg. head geometry crushes through rebar and prevents sticking in reinforced concrete
• Patented, high-performance, reinforced core flute maximizes energy transfer from the rotary hammer into the drill bit tip
• Proprietary flute geometry reduces vibration and optimizes impact energy transfer, enhancing drilling speed and durability while reducing noise and stress on the operator
• SDS-max shank with chisel-shaped drill bit head penetrates material and directs concrete dust into the multi-flute spiral

Specifications

• Model Number (MPN): MDMX08121Q
• Brand: Simpson Strong-Tie
• Shank Type: SDS-max Shank
• Head Type: Quad Head - 4x Drill Bit
• Diameter: 13/16 in.
• Overall Length: 21 in.
• Drilling Depth: 17 in.
• Material: Hardened Steel (Chromium-Nickel-Molybdenum Steel Alloy Body with Carbide Inserts)
• Standard Compliance: ANSI Standard B212.15
• Country of Origin: DE

Frequently Asked Questions

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

This drill bit features an SDS-max shank, which is designed to fit SDS-max rotary hammers. The SDS-max shank interface is a standard connection used across a wide range of professional-grade rotary hammer tools.

What is the actual drilling depth of the MDMX08121Q?

While the overall length of this drill bit is 21 in., the effective drilling depth is 17 in. This distinction is important when planning hole depths for anchor installations or other precise applications.

How does the quad-head design benefit drilling in reinforced concrete?

The 4 x 90 deg. quad-head geometry is specifically engineered to crush through rebar and prevent the bit from sticking in reinforced concrete. Combined with the high-volume double-helix flute design and patented reinforced core, the quad-head configuration improves both drilling speed and durability in tough, rebar-laden substrates.

What makes the body material of this drill bit particularly durable?

The drill bit body is constructed from a chromium-nickel-molybdenum steel alloy, which ensures hammering quality and extended service life. Additional heat-treatment procedures and a shot-peened finish further increase surface hardness, improve resistance to bending forces, and reduce overall drill bit wear during heavy use.

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