3" Knot Wire Cup Brush - Carbon Steel

Milwaukee 48-52-5040 – Product Description

What it is:

The 48-52-5040 is a Milwaukee 3" knotted wire cup brush used on angle grinders for heavy-duty surface cleaning and material removal.

Key specs:

• Type: Knotted wire cup brush
• Diameter: 3"
• Arbor/thread: 5/8"-11 (standard grinder mount)
• Material: Carbon steel wire
• Max RPM: ~12,000
• Tool use: 4-1/2" or 5" angle grinders

What it’s used for:

This is not a cutting blade—it’s an abrasive cleaning tool.

Typical uses:

• Removing rust from steel
• Cleaning welds and slag
• Stripping paint/coatings
• Surface prep on structural steel
• Heavy-duty fabrication cleanup

Key features:

• Knotted wire design: Aggressive cleaning action (more forceful than crimped brushes)
• High material removal: Quickly strips corrosion and buildup
• Rigid bristle structure: Better for tough, flat surfaces
• Durable carbon steel wire: Built for industrial use
• Grinder-mounted: Spins at high speed for mechanical abrasion

In plain terms:

This is basically a “steel scrubbing wheel” for a grinder.

Instead of cutting or drilling:

• it grinds away rust, paint, and scale
• used before welding, painting, or fabrication work