Products are made of high quality alloy steel production. The plates are punched and squeezed bores by precision technology. The pin, bush, roller are machined by high-efficiency automatic equipment and automatic grinding equipment, then through heat treatment of carburization, carbon and nitrogen protection mesh belt furnace, surface blasting process etc. Assembled precision by Internal hole position, spin riveted by pressure to ensure the performance of the entire chain. https://www.drivingchains.com/ch...smission-industrial.html