Norton 66623399003 Flap Disc 120 Grit Type 27 4.5 Inch

Product Description

The NORTON 66623399003 is a Type 27 flap disc designed for grinding, blending, and edge deburring on metal surfaces. It measures 4.5 inches in diameter with a 5/8-11 threaded arbor hole for secure mounting on standard angle grinders. The abrasive material is zirconia alumina — a durable, self-sharpening grain well suited to aggressive stock removal and finishing in one step. At 120 grit, this disc falls in the fine grade range, making it the right choice when the task calls for surface blending and light deburring rather than heavy material removal. Rated to 13,300 RPM, the disc carries a poly-cotton backing and plastic backing plate, and is trimmable for extended use. It belongs to the R828 series and ships individually.

This flap disc is used in metal fabrication shops, maintenance facilities, and field service environments where angle grinders are the primary tool. The Type 27 flat profile suits flat surface work and blending passes where the disc is held nearly parallel to the workpiece. Typical applications include weld blending, surface conditioning, and edge deburring on steel, stainless steel, and cast iron components. The fine 120 grit finish is appropriate for prep work ahead of coating or inspection. This disc is installed and operated by fabricators, ironworkers, pipefitters, and general maintenance trades.

Key Features

• 120 grit fine grade zirconia alumina abrasive for blending and deburring
• Type 27 flat profile for surface blending on flat and low-contour workpieces
• 5/8-11 threaded arbor hole fits standard angle grinder spindles directly
• Rated to 13,300 RPM for compatibility with common 4.5-inch grinders
• Trimmable disc extends usable life as flaps wear
• Poly-cotton backing with plastic backing plate — R828 series construction

Compatibility

Designed for use on steel, stainless steel, and cast iron. Fits angle grinders with a 5/8-11 threaded spindle accepting a 4.5-inch Type 27 flap disc.

Installation Notes

This disc is mounted and operated by qualified tradespeople using appropriate angle grinder equipment. Before mounting, confirm the grinder is unplugged or the circuit is de-energized, and verify the grinder's no-load RPM rating meets or exceeds the disc's 13,300 RPM maximum. Do not exceed the rated RPM under any circumstances. Wear ANSI-rated eye protection, a face shield, and gloves during operation, and inspect the disc for damage before each use.