Norton 66623399050 Flap Disc 40 Grit Type 29 4 Inch

Product Description

The NORTON 66623399050 is a Type 29 flap disc designed for aggressive material removal on metal fabrication, weld blending, and surface conditioning applications. Built with zirconia alumina abrasive at 40 grit, this coarse-grade disc cuts fast and holds up under sustained pressure. The fiberglass backing provides rigid support across the disc face, maintaining consistent abrasive contact and reducing flex during grinding. Rated at 15,300 RPM maximum, it is sized at 4 inches in diameter with a 5/8-inch arbor hole. Fabricators, ironworkers, and pipefitters typically reach for this disc when working with structural steel, stainless, or aluminum weldments.

This flap disc is suited for right-angle grinder use in both shop and field settings. The Type 29 conical profile delivers a larger contact area than a flat Type 27, making it well matched for blending welds on flat stock or removing mill scale from plate and pipe. The 40-grit coarse rating removes material quickly before transitioning to finer finishing steps. It performs in residential fabrication shops, commercial welding operations, and industrial maintenance environments where consistent stock removal matters.

Key Features

• 40-grit zirconia alumina abrasive for fast, coarse material removal
• Type 29 conical profile increases contact area for efficient weld blending
• Fiberglass backing provides rigid, durable support under load
• 15,300 RPM maximum speed rating for use on standard right-angle grinders
• 5/8-inch arbor hole fits common grinder spindle sizes
• Blue disc color allows quick grit identification on the job

Compatibility

Designed for use with right-angle grinders accepting a 4-inch disc with a 5/8-inch arbor attachment. Verify that the grinder's no-load RPM does not exceed the 15,300 RPM disc rating before mounting.

Installation Notes

A licensed fabricator or qualified operator should mount flap discs following ANSI B7.1 safety standards for abrasive wheels. Power down and disconnect the grinder before mounting or changing the disc. Inspect the disc for damage before each use and confirm the grinder guard is properly positioned. Never exceed the maximum RPM marked on the disc.