Product Specification
2-3/4" X 5/8"-11 KNOTTED CUP BRUSH - CARBON STEEL
When a flat steel surface is covered in heavy rust, scale, weld residue, paint, or stubborn buildup, the 2-3/4" x 5/8"-11 Knotted Cup Brush - Carbon Steel brings aggressive cleaning power to a compact footprint. Built with 0.020" carbon steel wire, this cup brush is designed for demanding surface preparation where a lighter crimped brush may not provide enough cutting action.
The knotted wire construction bundles the wire into stiff, tightly twisted sections that maintain a firm working edge under load. Combined with the cup shape, that gives the brush a broad, stable contact area for cleaning plate, fabricated assemblies, weldments, structural components, and other metal surfaces while still staying compact enough to work around edges and tighter areas.
A 2-3/4" diameter, 5/8"-11 threaded arbor, and 14,000 RPM maximum rating make this a strong fit for compatible professional angle grinders used in welding, fabrication, maintenance, and repair. It is the kind of brush you reach for when the job calls for fast, aggressive cleaning without stepping up to a larger cup wheel.
Product Specifications
| Specification |
Details |
| Diameter |
2-3/4" |
| Wire Material |
Carbon Steel |
| Wire Diameter |
0.020" |
| Wire Style |
Knotted |
| Brush Type |
Cup Brush |
| Arbor |
5/8"-11 Threaded |
| Maximum RPM |
14,000 |
Features
-
Aggressive knotted-wire construction for medium- to heavy-duty surface cleaning
-
0.020" carbon steel wire attacks stubborn rust, scale, weld residue, paint, and buildup
- Cup-style geometry provides a broad working area for fast surface cleaning
- Compact 2-3/4" diameter provides good control and access around fabricated parts
- Stiffer and more aggressive than flexible crimped-wire cup brushes
-
5/8"-11 threaded arbor for quick spin-on installation
- 14,000 RPM maximum rating
- Excellent for welding, fabrication, maintenance, repair, and general steel preparation
- Strong choice for flat surfaces, plate, weldments, structural components, and fabricated assemblies
Applications & Performance
Knotted cup brushes are built for aggressive broad-surface cleaning. Their cup-shaped profile places multiple wire knots against the workpiece at once, making them especially effective when you need to clean more surface area than a narrow wire wheel can cover.
Common applications include:
- Heavy rust and corrosion removal
- Mill scale removal
- Weld cleanup
- Removing weld spatter and residue
- Paint and coating removal
- Oxidation removal
- Cleaning steel plate
- Surface preparation before welding
- Cleaning fabricated assemblies
- Structural-steel maintenance
- Preparing metal before coating or repair
- General industrial maintenance
The compact cup shape provides strong surface contact while remaining easier to control around smaller workpieces and fabricated details. Use controlled pressure and let the wire tips perform the cleaning rather than forcing the brush into the workpiece.
Materials
Recommended for cleaning and surface preparation on compatible ferrous materials, including:
- Carbon steel
- Mild steel
- Structural steel
- Cast iron
- Wrought iron
- Other compatible ferrous metal surfaces
Keep carbon steel brushes dedicated to ferrous work when cross-contamination matters. For stainless-steel applications where iron contamination must be minimized, use a dedicated stainless steel wire brush.
Machine Compatibility
Use this 2-3/4" cup brush on a compatible angle grinder with a 5/8"-11 spindle, adequate brush capacity and a maximum speed no greater than 14,000 RPM. Match the actual hub seating and allow room for wire flare.
Compatible examples include:
-
Benchmark Abrasives BMT-AGBC4570_1 — 4-1/2" corded angle grinder; 5/8"-11 spindle; 11,000 RPM.
-
Makita® 9557PB — 4-1/2" angle grinder; 11,000 RPM.
-
Milwaukee® 2880-20 — 4-1/2" / 5" angle grinder; 8,500 RPM.
-
Milwaukee® 2881-20 — 4-1/2" / 5" angle grinder; 8,500 RPM.
Other machines may be compatible. Use the manufacturer-specified wire-brushing setup and guard, with secure hub engagement and adequate operating clearance. Other grinders meeting these requirements may also be suitable.
Safety Tips
- Never exceed the brush's 14,000 RPM maximum speed.
- The brush's rated RPM must meet or exceed the maximum operating speed of the power tool.
- Confirm the grinder is designed to safely accommodate the cup brush and its operating wire flare.
- Inspect the brush before every use and replace it if damaged, excessively worn, loose, or distorted.
- Confirm the 5/8"-11 threaded arbor is fully seated and secure before operation.
- Use the appropriate grinder guard and maintain adequate clearance around the rotating brush.
- Wear proper PPE, including eye and face protection, hearing protection, gloves, appropriate clothing, and respiratory protection when required.
- Keep bystanders away from the work area and direction of rotation.
- Use controlled pressure. Excessive force bends the wire and can accelerate wire fatigue.
- Allow the grinder to reach operating speed before contacting the workpiece.
- Follow all operating and safety instructions for both the power tool and wire brush.
