The roundness Belt Conveyor Roller Idler is controlled in special tolerance scope. The axle is manufactured by fine cold drag steel according to standard tolerance. The bearing housing has been manufactured after stamping many times by the imported cold griped steel. The idler shell and bearing housing have been welded together by the automatic welding machinery hand. Then it forms a whole high strength structure. The bearing, which uses the world famous brand, is the big roving crack, deep groove ball and double sealing bearing. It makes the idler has the ideal static and dynamic balance that is better than the national standard.