Norton 66623399004 Ceramic Alumina Flap Disc 40 Grit

Product Description

The NORTON 66623399004 is a Type 27 ceramic alumina flap disc engineered for aggressive material removal on metal, stainless steel, and hard alloys. It carries a 40 grit coarse rating, making it suited for weld blending, surface prep, and heavy stock removal where a fast cut rate and long disc life are required. The polyester backing resists heat and flex fatigue through extended grinding cycles. With a rated maximum speed of 13,300 RPM and a 4.5-inch diameter, this disc is designed for standard 4.5-inch right-angle grinders used daily in fabrication, welding, and maintenance trades.

This flap disc fits 4.5-inch angle grinders with a 7/8 inch arbor. The Type 27 flat profile keeps the disc flush to the workpiece, which favors flat surface grinding and weld seam blending over edge work. The trimmable design allows the operator to expose fresh abrasive as the disc wears, extending usable life on the job. It is commonly used by ironworkers, welders, pipefitters, and metal fabricators working on structural steel, plate, and pipe.

Key Features

• Ceramic alumina abrasive delivers faster cut rates and longer life compared to standard aluminum oxide on hard metals
• 40 grit coarse grade for aggressive stock removal and weld blending
• Type 27 flat profile for flush surface grinding
• Polyester backing for heat resistance and flex durability
• Trimmable construction to expose fresh abrasive as disc wears
• Rated to 13,300 RPM for use on standard 4.5-inch angle grinders

Compatibility

Designed for use on 4.5-inch angle grinders equipped with a 7/8 inch arbor. Fits standard right-angle grinders commonly used in metal fabrication, welding, and industrial maintenance applications.

Installation Notes

Installation and disc changes must be performed by the operator with the grinder fully powered off and disconnected from the power source. Verify the grinder spindle speed rating meets or exceeds 13,300 RPM before mounting. Inspect the disc for cracks or damage before each use and do not use a damaged disc. Follow ANSI B7.1 and applicable OSHA standards for abrasive wheel mounting and guarding.