Tru-maxx 88537 Knotted Cup Brush 3.5 in Steel Wire

Product Description

The TRU-MAXX 88537 is a knotted steel wire cup brush designed for aggressive surface preparation and weld cleaning on angle grinders and other threaded-arbor power tools. It features a 3.5-inch brush diameter with 0.023-inch knotted steel wire fill, which delivers the increased cutting action and durability needed for heavy rust removal, mill scale stripping, and surface conditioning on metal workpieces. The 5/8-11 threaded arbor mounts directly to standard angle grinders without adapters. Rated to 13,000 RPM maximum, this brush is built for professional-grade production work. Licensed tradespeople and metal fabricators working in HVAC, plumbing, and general mechanical trades rely on this style of brush for pre-weld and post-weld surface prep.

This cup brush is suited for use on structural steel, pipe, plate, and fabricated assemblies where surface contamination must be removed before coating, welding, or inspection. The single-row knotted wire configuration concentrates wire tension for faster stock removal compared to crimped wire designs. It is commonly used by HVAC installers, pipefitters, welders, and maintenance mechanics on both shop and field work. The 7/8-inch trim length provides consistent wire exposure throughout the usable life of the brush.

Key Features

• Knotted steel wire construction for aggressive rust, scale, and weld spatter removal
• 3.5-inch brush diameter provides broad contact area on flat and curved surfaces
• 0.023-inch wire diameter balances cutting aggression with wire fatigue resistance
• 5/8-11 threaded arbor fits standard angle grinders without additional adapters
• 13,000 RPM maximum rating suits most 4-inch to 4.5-inch angle grinders
• Single-row knotted wire design maintains consistent wire tension throughout brush life

Compatibility

Designed for use with angle grinders and die grinders equipped with a 5/8-11 threaded arbor spindle, which is the standard thread on most 4-inch and 4.5-inch angle grinders.

Installation Notes

Installation and operation should be performed by a qualified tradesperson familiar with angle grinder safety requirements. Always disconnect the grinder from power before mounting or removing the brush. Verify that the tool RPM rating meets or exceeds the 13,000 RPM maximum rating of this brush before use, and confirm the spindle thread is 5/8-11 before mounting. Operators must wear appropriate PPE including eye and face protection rated for wire wheel use, as wire bristle ejection is a recognized hazard with knotted wire brushes.