Osborn 0003357400 Knotted Cup Brush 4 in Steel Wire

Product Description

The OSBORN 0003357400 is a knotted steel wire cup brush designed for heavy-duty surface preparation and weld cleaning on metal workpieces. Measuring 4 inches in diameter with a 0.014-inch wire diameter, this single-row cup brush delivers aggressive cutting action for removing rust, mill scale, weld spatter, and coatings. The knotted wire construction concentrates wire tension, increasing abrasive force compared to crimped wire designs. It mounts via a 5/8-11 threaded arbor hole, making it compatible with standard right-angle grinders. Metalworkers, fabricators, pipefitters, and maintenance technicians install this brush for surface conditioning and weld prep tasks.

This cup brush is suited for use on structural steel, pipe, fabricated assemblies, and general industrial metalwork in both shop and field environments. The 5/8-11 arbor interface is a widely used standard on 4-inch to 4.5-inch angle grinders, making installation straightforward. Typical applications include post-weld cleanup, rust removal, and surface prep prior to painting or coating. The single-row knotted configuration delivers consistent contact pressure across irregular or curved surfaces.

Key Features

• 4-inch diameter knotted steel wire cup brush for aggressive surface preparation
• 0.014-inch wire diameter provides high-tension cutting action
• 5/8-11 threaded arbor hole fits standard angle grinders
• 1.25-inch trim length for controlled wire deflection and consistent finish
• Single-row construction maintains focused contact on workpiece surfaces
• Rated to 6,000 RPM maximum for use with standard grinder speeds

Compatibility

Designed for use with angle grinders equipped with a 5/8-11 threaded spindle, the standard arbor size for most 4-inch and 4.5-inch right-angle grinders used in metal fabrication and maintenance trades.

Installation Notes

Installation and use should be performed by qualified metalworkers or tradespeople familiar with angle grinder safety. Always power down and disconnect the grinder before mounting or removing the brush. Verify that the grinder spindle speed does not exceed the 6,000 RPM maximum rating stamped on the brush before operation. Wear appropriate PPE including a face shield, safety glasses, and gloves, and ensure the work area is clear of bystanders during operation.