If the chain saw chain is broken, replace it with another chain. 1: Open the saw chain cover and remove it. 2: Observe that there is a screw that can adjust the chain tightness under the saw chain and loosen the screw. 3: Remove the saw chain. 4: Cleaning. 5: Load the new saw chain, pay attention to the blade direction, and keep the same blade direction as the old one. 6: Tighten the chain adjusting screw, the tightness requirement is two chain links, which means it can be pulled up gently. 7: Cover the back of the saw chain, and turn the chain while tightening until it is tight. 8: Start and see if there is any oil dumping. China saw chains manufacturers