Norton 66252838868 Knotted Cup Brush 3.5in Carbon Steel

Product Description

The NORTON 66252838868 is a knotted carbon steel cup brush designed for aggressive surface preparation on metal and masonry. At 3.5 inches in diameter with a single-row knotted wire fill, it delivers concentrated abrading action for removing weld spatter, rust, mill scale, and heavy coatings. The wire diameter is 0.02 inches, providing a balance of stiffness and coverage. Rated to 13,000 RPM, this brush is built for use with standard right-angle grinders. A 5/8-11 threaded arbor hole ensures direct mounting without adapters on most grinders. Licensed tradespeople and fabricators performing surface prep, weld cleaning, and paint stripping are the primary installers and users of this tool.

This cup brush is suited for both residential and light commercial metalworking, fabrication shops, HVAC duct work, structural steel prep, and pipeline maintenance. The knotted wire construction is preferred when work involves heavy rust removal or cleaning of pitted or irregular surfaces where a crimped brush would wear too quickly. The 1.375-inch trim length gives the brush a firm, controlled cut. The single-row configuration concentrates the wire contact for edging work and detailed weld bead cleaning.

Key Features

• Knotted carbon steel wire fill for aggressive material removal and extended wear life
• 3.5-inch brush diameter for broad surface contact on flat and curved workpieces
• 0.02-inch wire diameter balances stiffness with consistent wire-to-surface contact
• 5/8-11 threaded arbor hole fits most standard right-angle grinders without an adapter
• 13,000 RPM maximum speed rating for compatibility with common grinder operating speeds
• 1.375-inch trim length provides a firm, stable brushing action

Compatibility

Designed for use with right-angle grinders equipped with a 5/8-11 threaded spindle, which is the standard thread found on most 4-inch to 5-inch angle grinders used in metalworking and fabrication trades.

Installation Notes

This brush is installed and operated by metalworkers, pipefitters, welders, and HVAC fabricators. Always ensure the grinder is disconnected from power before mounting or removing the cup brush. Verify the grinder spindle speed does not exceed the 13,000 RPM maximum rating marked on the brush before operation. Wear appropriate PPE including a full face shield, gloves, and hearing protection when operating wire brushes at speed.