Some steel brushes are very simple and must be used by moving them back and forth on an object to scrape dirt and rust off. Other steel brushes are used to be made with power tools so that the brush produces more friction and is able to clean more effectively.
One type of steel brush that is made to be used with power tools is called a cup brush. A cup brush is made in a cupped shape with the ends of the steel wires pointing straight out. This attachment can be used with a power drill to spin at high speeds.
A cup brush is used in light and medium duty applications to clean flat or irregular surfaces as well as bevel buffing. There are several manufacturing styles for cup brushes. A traditional cup brush just has steel wires extending from it in a circle all the way around the head. For more heavy duty uses, cup brushes are made with a series of spiraled steel wires that are more like thick cables.
Miniature cup brushes connected to a long arm are also made to clean hard to reach areas or components. The mounting portion of cup brush usually has a threaded hole or a stem that can be fitted into a drill head or some other rotation machine. A cup brush with a threaded nut is usually designed specifically for use with an angle grinder for smooth and efficient operation. Most power tools that are used with cup brushes have varying speeds to help control the operation of the brush.
Cup brushes are very common in the welding industry where they are used along with other steel brushes to put the finishing touches on metal products. A cup brush can be used to smooth out newly welded joints and get a product ready for paint. Welding professionals are always careful to make sure no flammable chemicals or other materials are present when they use a steel brush because the friction at high speeds creates a wave of sparks.