Product Specification
3" X 5/8"-11 KNOTTED CUP BRUSH - CARBON STEEL
When rust, scale, weld residue, paint, and heavy surface buildup need to come off fast, the 3" x 5/8"-11 Knotted Cup Brush - Carbon Steel delivers aggressive cleaning power across a broader working area. Built with 0.020" carbon steel wire, it is made for demanding metal preparation where a flexible crimped brush may not cut aggressively enough.
The knotted wire construction bundles the wire into stiff, tightly twisted sections that stay firm under load and concentrate more cleaning force at the wire tips. Combined with the cup shape, that gives the brush strong, stable surface contact for cleaning steel plate, weldments, fabricated assemblies, structural components, and other broad metal surfaces.
Its 3" diameter provides a little more coverage than the compact 2-3/4" cup while remaining easy to control around fabricated parts and edges. A 5/8"-11 threaded arbor allows quick spin-on installation on compatible angle grinders, and the brush carries a 14,000 RPM maximum rating for properly matched equipment.
Product Specifications
| Specification |
Details |
| Diameter |
3" |
| 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 rust, scale, weld residue, paint, and stubborn buildup
- Cup geometry creates a broad, stable working area for efficient surface cleaning
-
3" diameter balances increased coverage with maneuverability
- 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 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 simultaneously, helping remove stubborn buildup efficiently across flat and moderately contoured metal surfaces.
Common applications include:
- Heavy rust and corrosion removal
- Mill scale removal
- Weld cleanup
- Removing weld residue and spatter
- 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 3" cup profile provides more surface coverage than smaller cup brushes without moving into the bulk of a large-diameter cup. Use controlled pressure and allow the wire tips to perform the cleaning rather than forcing the brush into the surface.
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 3" 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.
