Norton 66623399175 Flap Disc 4-1/2 in 120 Grit Type 29

Product Description

The NORTON 66623399175 is a Type 29 ceramic alumina flap disc designed for aggressive material removal and blending on metal surfaces. The disc measures 4-1/2 inches in diameter with a 7/8-inch arbor hole and carries a 120-grit fine-grade abrasive bonded to a polyester backing. Ceramic alumina cuts cooler and lasts longer than standard aluminum oxide under heavy grinding loads. Rated to 13,300 RPM, this disc fits standard angle grinders used daily by fabricators, pipefitters, and welders. The Type 29 conical flap geometry maintains consistent abrasive contact on flat and contoured workpieces, making it well-suited for finishing passes that also require light stock removal.

This flap disc is used in metal fabrication, structural steel work, pipe fitting, and MRO grinding applications where a fine finish with controlled material removal is needed. The 120-grit rating makes it appropriate for weld blending, surface prep before coating, and deburring operations on ferrous and non-ferrous metals. It is a single-disc package sold in minimum quantities of 10, consistent with professional shop and field use. Typical users include certified welders, ironworkers, sheet metal mechanics, and maintenance technicians working in industrial and commercial settings.

Key Features

• Type 29 conical geometry for flat and contoured surface contact
• Ceramic alumina abrasive for extended disc life and cooler cutting action
• 120-grit fine grade suited for weld blending and pre-coat surface preparation
• Polyester backing resists heat and flexing under load
• 13,300 RPM maximum speed rating for standard 4-1/2 inch angle grinders
• 7/8-inch arbor hole fits common grinder spindle configurations

Compatibility

Designed as a direct-mount replacement flap disc for 4-1/2 inch angle grinders with a 7/8-inch arbor spindle.

Installation Notes

Flap discs must be installed and changed by a qualified operator following the grinder manufacturer's guard and speed requirements. Always confirm the grinder's no-load RPM does not exceed the 13,300 RPM disc rating before mounting. Power down and disconnect the grinder from its power source before disc changes. Wear appropriate PPE including a face shield and gloves during installation and operation in accordance with applicable ANSI B7.1 and OSHA abrasive wheel standards.