... best raw material by spectrometer and strictly control the surface qualities and inner hardness and metallo-graphic structure;3) ... etc., Caterpillar, Komatsu, Hitachi, Daewoo, Hyundai, Kobelco and other reputed brands, or according to your drawings, specifications or ... in manufacturing all kinds and sizes of bearings and bushings, bolts and buts, track chain, track shoes, and other excavator parts. ...