Osborn 0003300000 Knotted Cup Brush 3.5 in Steel Wire

Product Description

The OSBORN 0003300000 is a knotted steel wire cup brush designed for aggressive surface preparation on angle grinders and bench grinders. With a 3.5-inch brush diameter and 0.02-inch wire diameter, the knotted wire fill delivers concentrated cutting action for removing weld scale, rust, mill scale, paint, and surface coatings from metal workpieces. The single-row knotted construction maintains consistent contact pressure across the work surface. Rated to 12,500 RPM maximum, this brush is suited for high-speed grinder applications where a flared or crimped wire brush would not provide enough aggression. The 5/8-11 threaded arbor hole fits the standard spindle thread found on most angle grinders.

This cup brush is used in metal fabrication, welding prep and cleanup, structural steel work, and general industrial maintenance. Typical applications include weld bead cleanup, rust and oxidation removal, and paint stripping on ferrous metal surfaces. The 7/8-inch trim length provides a moderate wire exposure that balances flex with cutting aggressiveness. It is appropriate for both shop and field use wherever an angle grinder with a 5/8-11 spindle is available.

Key Features

• Knotted steel wire fill for aggressive material removal on hard surfaces
• 3.5-inch brush diameter provides broad contact coverage in cup configuration
• 0.02-inch wire diameter balances wire stiffness with surface reach
• 5/8-11 threaded arbor hole fits standard angle grinder spindles
• 12,500 RPM maximum speed rating for high-speed grinder compatibility
• Single-row construction for focused, consistent cutting action
• 7/8-inch trim length delivers controlled wire flex during use

Compatibility

Designed for use with angle grinders and similar power tools equipped with a 5/8-11 threaded spindle, which is the standard arbor size on most 4-inch to 5-inch angle grinders used in metal fabrication and welding trades.

Installation Notes

Installation and use of wire cup brushes should be performed by qualified personnel familiar with abrasive product safety. Always power down and disconnect or de-energize the grinder before mounting or removing the brush. Confirm the tool RPM rating meets or does not exceed the 12,500 RPM maximum marked on this brush before operation. Wear appropriate PPE including a face shield, safety glasses, and gloves, and follow ANSI B11 and OSHA 29 CFR 1910.243 guidelines for abrasive wheel and brush use.