Osborn 0003357500 Knotted Cup Brush 4in Steel

Product Description

The OSBORN 0003357500 is a knotted steel cup brush designed for aggressive surface preparation on metal, welds, and castings. The knotted wire construction delivers concentrated cutting action, making it effective for removing rust, scale, weld spatter, and heavy mill scale. The brush measures 4 inches in diameter with a 0.025-inch wire diameter and a 1-1/4-inch trim length. It mounts via a 5/8-11 threaded arbor and is rated for a maximum of 6,000 RPM. Licensed tradespeople and fabricators use this brush with angle grinders for demanding surface conditioning and weld cleanup tasks.

This cup brush is suited for industrial and trade applications involving carbon steel, structural steel, and fabricated assemblies. Typical use cases include pre-weld and post-weld cleaning, rust and corrosion removal, and surface preparation prior to coating or painting. The single-row knotted fill pattern concentrates wire contact force, which is well matched to heavy-duty cleaning on flat and slightly contoured surfaces in both shop and field environments.

Key Features

• Knotted wire construction for aggressive material removal and long service life
• 4-inch brush diameter for broad surface coverage with an angle grinder
• 0.025-inch wire diameter balances cutting aggression with wire durability
• 5/8-11 threaded arbor for direct mounting on standard angle grinders
• 1-1/4-inch trim length provides controlled wire deflection and consistent pressure
• 6,000 maximum RPM rating for safe operation on compatible grinders

Compatibility

Designed for use with angle grinders equipped with a 5/8-11 threaded spindle, which is the standard arbor size on most 4-inch and 4-1/2-inch angle grinders.

Installation Notes

Installation and operation should be performed by qualified personnel familiar with abrasive power tool safety. Always verify the grinder spindle speed does not exceed the 6,000 RPM maximum rating marked on the brush before mounting. Wear appropriate PPE including a face shield, gloves, and hearing protection during operation. Inspect the brush for damaged or broken wires before each use and remove it from service if defects are found.