How to Choose Cup Brushes

Cup brushes are surface finishing and deburring tools that feature a cup-like body to which filaments attach. A type of power brush, these rotary brushing tools have metal or nylon abrasive filaments and come in a variety of tool diameters. Cup brushes are designed for use with grinding tools, and have a 5/8"-11 arbor hole or integral shaft for connecting the industrial brush to powered equipment or even machinery.

For industrial buyers, choosing a cup brush requires an understanding of cup brush types and product specifications. Many different types of cup brushes are available, and filament type is an important consideration.  Wire cups are best suited for burr removal and surface preparation on large surfaces. Nylon abrasive cups are ideal for light deburring, edge blending, and general surface finishing. Other applications for cup-style power brushes include rust, paint, and weld scale removal.

Wire Cup Brushes

When choosing wire brushes, buyers need to specify wire size, filament material, and wire style or type. Typically, wire sizes are given as decimal measurements. The larger the wire size and thickness, the more aggressive the brush. Stainless steel and carbon steel are common filament materials. Carbon steel is more aggressive than stainless steel, but can leave “after rust” on the workpiece surface. Stainless steel doesn’t leave residues that can oxidize, but these wire brushes are less aggressive than carbon steel brushing tools. 

In terms of wire style or type, buyers can also choose crimped or knotted wire brushes. Wire size and material are important, but wire style is critical to abrasiveness and aggressiveness. Crimping allows the metal filaments to better support each other than with straight bristles. Crimped brushing tools are more flexible than knot-style cup brushes, but crimped brushes are also less aggressive. For heavy-duty surface finishing and burr removal applications then, knotted wire brushes are recommended.

Single Row, Double Row, and Cable Twist

Knot-type cup brushes are available in single row, double row, and cable twist designs. Single-row, knot-type brush tools are used for the removal of burrs, weld scale, paint and rust, as well as edge blending and surface preparation. Double-row, knot-type cup brushes provide fast cutting and cleaning over wide areas. Both single-row and double-row power brushes feature filament ends that are loosely twisted and tufted for more flexibility.  

By contrast, knot-type cup brushes with a cable twist have wide, tightly-twisted ends for more aggressive brushing. Applications for these cup-style industrial brushes include heavy-duty burr removal, surface preparation, and surface finishing. Like other types of wire cups, these surface finishing and deburring tools are available in different diameters and with an arbor hole for attachment to grinding tools and equipment.

Abrasive Nylon Cup Brushes

As a full-line supplier of surface finishing solutions, Brush Research Manufacturing (BRM) also provides cup brushes with abrasive nylon filaments. Cup brush nylon abrasive brushing tools are available with aluminum oxide and silicon carbide abrasives in a variety of grit sizes. Abrasive nylon cups are non-reactive, and provide an alternative to steel wire brushes for applications such as light deburring, edge blending, and general surface finishing.   

Abrasive nylon cup brushes can be used in hand operations and with automated equipment, including CNC machinery. Available in different diameters, some of these power brushes feature a 5/8"-11 threaded arbor hole. Others have an integral shaft for use with handheld grinding tools and powered equipment. As with all power brushes, including wire cup brushes, maximum safe free speed (MSFS) in an important specification to consider. For more information about cup brushes, watch this short video.