A21 Grinding Bits | McMaster-Carr

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1/4"

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Shape Number

Shank Length

Nylon Mesh Grade

For Use With

Grinders for Bits and Burs

Maximum Rotation Speed

34,500 rpm

35,510 rpm

DFARS Specialty Metals

Exempt

Export Control Classification Number (ECCN)

REACH

RoHS

Rotation Speed

30,000 rpm to 99,999 rpm

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

Grit Rating

Surface Texture

For Finish

Form

6 Products

Nylon Mesh Cushioned Sanding Bits

Style A

The abrasive-embedded mesh construction gives you more control over sanding pressure, creating finer and more consistent finishes in small, recessed, and hard-to-reach areas.

1/4" Dia. × 1 1/2" Lg. Shank

Style A

Coarse Grade—Coarse grade is for aggressive deburring and cleaning.

Medium Grade—Medium grade is for deburring and polishing.

Fine Grade—Fine grade is for light blending and finishing.

	Dia.	Lg.	Nylon Mesh Grade	For Finish	Max. Rotation Speed, rpm	Color	Abrasive Material	Abrasive Backing Material	For Use On	For Use With		Each
Style A



	A21	1"	1"	Coarse	Rough	34,500	Gray	Aluminum Oxide	Nylon Mesh	Steel, Wood	Drills, Grinders for Bits and Burs	4630A112	000000


	A21	1"	1"	Medium	Smooth	34,500	Gray	Aluminum Oxide	Nylon Mesh	Steel, Wood	Drills, Grinders for Bits and Burs	4630A111	00000
	A21	1"	1"	Fine	Extra Smooth	34,500	Gray	Silicon Carbide	Nylon Mesh	Steel, Wood	Drills, Grinders for Bits and Burs	4630A113	00000

Grinding Bits for Metals

Style 3

Made of aluminum oxide, these bits are well suited for use on most metals and materials that are not heat sensitive.

Bits are also known as mounted points and die grinder bits. Head diameter is measured at the widest point.

Caution: As bit shank is exposed beyond _1/2", maximum safe rpm decreases significantly. Refer to ANSI standard B7.1. Use only accessories that have a greater rpm rating than the maximum speed of the grinder you choose.

Barrel

Style 3

		Head				Abrasive
	Style	Dia.	Lg.	Max. Rotation Speed, rpm	Shape No.	Material	Bond Material	Shank Lg.	Choose a Grit (Surface Texture)	Pkg. Qty.		Pkg.
For Steel, Stainless Steel, and Iron







				1/4" Diameter Shank

				3	1"	1"	34,500	A21	Aluminum Oxide	Vitrified Clay	1 1/2"	36 (Rough) Blue-Gray, 60 (Rough) Orange, 120 (Smooth) Blue	5	4522A269	000000

High-Performance Grinding Bits for Metals

Style

Made of aluminum oxide ceramic, these bits prevent material and heat buildup better than bits made of boron nitride and aluminum oxide when used on steel, stainless steel, iron, and titanium. They also last longer than boron nitride bits, so they’re the best choice for high-volume applications. Also known as mounted points and die grinder bits.

Head diameter is measured at the widest point.

Barrel

Style

		Head				Abrasive
	Style	Dia.	Lg.	Max. Rotation Speed, rpm	Shape No.	Material	Bond Material	Shank Lg.	Grit (Surface Texture)		Each
For Iron, Stainless Steel, Steel, and Titanium







				1/4" Diameter Shank

				11	1"	1"	35,510	A21	Ceramic Alumina	Vitrified Clay	1 1/2"	80 (Smooth) Green	4775N22	00000

Hex-Shank Grinding Bits for Metals


Style 2	Hex Shank

Use bits in any drill chuck that accepts a _1/4" hex shank.

Bits are aluminum oxide, which is the most common abrasive used in grinding metal. They are also known as mounted points and die grinder bits. Head diameter is measured at the widest point.

Barrel


Style 2	Hex Shank

		Head				Abrasive
	Style	Dia.	Lg.	Max. Rotation Speed, rpm	Shape No.	Material	Bond Material	Shank Lg.	Grit (Surface Texture)		Each
For Steel and Iron







				1/4" Hex Shank

				2	1"	1"	34,500	A21	Aluminum Oxide	Vitrified Ceramic	1 1/2"	60 (Rough) Gray	4087A15	00000