... . Coal,iron ore,port etc. idlerFree roller,Tapered roller,Grooved roller,Sprocket roller,Drive taper roller,Accumulating roller etc.Roller DiaShaftDiaTube ThicknessRoller LengthTube structureSurface treatmentErecting structureΦ16 ... ,Coat rubber,Carbon steel ,Stainless steel , Aluminium alloy galvanization\chromeplate\skin glue\plastic\injectiona.spring shaftb.mandrel shaftc.inside thread shaftd ...