Osborn OSB99041 Knot Wire Cup (4" OD X .020" Steel X 5/8-11 Nc AH){Clamshell}

The Osborn OSB99041 is a knot wire cup brush, 4 inch outside diameter, .020 inch steel wire, 5/8-11 NC arbor hole, clamshell packaged.

This is the heavy configuration: knot construction at .020 inch wire, which is the top of the aggression scale in this range.

Knot construction is what makes it work. The wire is twisted into tight rigid bundles, and a rigid bundle strikes the surface rather than sweeping across it. Crimped wire at the same gauge would flex on contact and polish. The distinction decides everything: crimped brushes clean, knot brushes remove.

At .020 inch that removal is real — mill scale, heavy rust, slag, and coatings. It is also why this is the wrong brush for anything that has to look good afterward. A .020 knot cup on light material gouges it, and the .014 cup in this range exists for that reason.

The cup geometry covers area where a wheel works a line, which is what surface preparation actually needs: stripping a panel rather than cleaning out a groove.

The 5/8-11 NC arbor is the threaded angle grinder standard.

Steel wire means carbon steel only. On stainless it embeds carbon particles that rust weeks later and destroy the passive layer.

Verify rated speed against the grinder, and wear a full face shield — a .020 knot cup throws wire with real energy.

Brand

Osborn

SKU

OSB99041

Category

Abrasives

Weight

0.64 lbs

Dimensions

11.00 x 1.25 x 1.25

Price

$24.00

Availability

Call for pricing

Rating

3.79 / 5.0