... .1-1999 standard production of hard-toothed surface transmission device,which has two parts of ... of gear transmission, low noise.2, distribution box small helical gear cone Angle, using qualitative, 38GrMoAl ... precision, high hardness.3, adopt ductile iron box and high strength thrust self-aligning roller bearings ... in 24 hours. gearbox hard surface gear box for plastics extruder gearbox manufacturer