Abstract: An end brush and a method of making the brush is disclosed using the automatic distribution and insertion of the bristle fill material into the cup of a cup-shape shank holder. A centered drive stem projects from the bottom of the holder. After a measured amount of the fill material is inserted through fill tubes and a guide funnel, a centering core insert is forced into the center of the cup to distribute the fill material around and against the interior wall of the cup. The material is cut to proper length and in the same or a separate station the exterior wall of the cup of the holder is deformed or crimped inwardly girdling the core securing and centering the core and material in the holder. Axial ribs are also formed which improves transfer of heat from the holder improving tool life. Preferably the insert is softer than the fill material and may also be softer than the holder. A wide variety of fill materials may be employed as well as various shapes of inserts and holders.

Abstract: An end brush and a method of making the brush is disclosed using the automatic distribution and insertion of the bristle fill material into the cup of a cup-shape shank holder. A centered drive stem projects from the bottom of the holder. After a measured amount of the fill material is inserted through fill tubes and a guide funnel, a centering core insert is forced into the center of the cup to distribute the fill material around and against the interior wall of the cup. The material is cut to proper length and in the same or a separate station the exterior wall of the cup of the holder is deformed or crimped inwardly girdling the core securing and centering the core and material in the holder. Axial ribs are also formed which improves transfer of heat from the holder improving tool life. Preferably the insert is softer than the fill material and may also be softer than the holder. A wide variety of fill materials may be employed as well as various shapes of inserts and holders.