A pole piece (106) for a rotor (100) of a rotary electric machine (20) includes a hub portion (104) and a plurality of pole segments (106) distributed evenly about the hub portion (104). The pole segments each have a base (116) that is connected to the hub portion (104) and a tip (118) that is disposed axially opposite the base (116) along an axis (60) of the pole piece (106). Each pole segment (106) defines circumferentially opposite side surfaces (120, 122) that extend between the base (116) and the tip (118). Each pole segment (106) also defines radially opposite outer and inner surfaces (124, 126) that extend between the side surfaces (120, 122). A groove is recessed in the side surfaces (120, 122) of each pole segment (106). A radially innermost portion (136) of the groove (130, 132) is arranged proximate to the radially outer surface.