When crimping rubber hose joints, if the crimping size is too large, the inner rubber layer and winding steel wire of the hose will be crushed, causing oil leakage. If the size is insufficient, excessive pressure during use can cause oil leakage, and even high oil pressure can cause the hose joint to come out directly. If it hits the worker, it can cause injury or death. So please be sure to grasp the reasonable size of the attachment, based on the shrinkage of the inner hole at the end of the joint. The compression of the national standard joint is 0.1-0.4mm, and the compression of the ordinary joint is 0.1-1mm. Also, due to different manufacturers of rubber hoses and joint sleeves, the size also varies.