... A3 Hardend Teeth processing: forging hobbing, quenching. CNC machine european standard roller chain sprockets ,plate wheel, chain sprocket, taper ... sprockets etc.Material: C45, A3.... according to ISO, DIN,ANSI,JIS,BS,KANA,SATI standardchain sprocket, taper bore ... are the professional manufacturer for all kinds of sprockets, European standard series and American standard series.standard sprocket, ...