SDS Max 4CT MX4™ 1-1/8" X 17" X 21"

The Milwaukee SDS Max 4CT MX4™ 1-1/8" x 17" x 21" is a heavy-duty, long-reach rotary hammer drill bit built for large-diameter drilling in concrete, reinforced concrete, and masonry. This is a step up into deep drilling territory, where both durability and stability become critical.

Performance & Design

• Solid carbide 4-cutter head
  Delivers up to 5x longer life in concrete with rebar and maintains cutting efficiency in tough aggregate
• 4-cutter geometry
  Reduces lock-up when hitting rebar, keeping drilling smooth and controlled
• Rebar guards
  Protect cutting edges from premature wear in reinforced concrete
• Centering tip
  Improves accuracy and prevents walking at hole start
• Variable flute design
  Removes dust faster, reducing heat and improving drilling speed
• Wear mark indicators
  Show when the bit no longer meets ANSI spec for anchor holes

Size & Capacity

• Diameter: 1-1/8"
• Usable cutting depth: 17"
• Overall length: 21"
• Shank: SDS Max (for large rotary hammers only)

Ideal For:

• Deep anchor hole drilling
• Through-wall and structural penetrations
• Reinforced concrete (rebar) applications
• Commercial and industrial construction
• Mechanical, electrical, and plumbing installs

Quick takeaway:

This is a long-reach, large-diameter concrete bit—built for deep drilling in reinforced concrete without binding when hitting rebar, while maintaining accuracy and durability.

Where it fits in SDS lineup:

• SDS+ → light/medium duty drilling
• Short SDS Max → shallow, controlled holes
• MX4 1-1/8" x 12" x 17" → mid-depth precision work
• MX4 1-1/8" x 17" x 21" (this bit) → deep drilling + reach
• Core bits → oversized holes