Metal Box,Metal Tool Chest,Metal Hand Tool Box,Homemade Metal Tool Box xiacun factory , https://www.xiacunmetal.com When grinding requires a higher outer circle of the workpiece (Fig. 1), we used a double-cone end-expanding mandrel with low efficiency. To this end, we designed a four-cone elastic expansion mandrel. The two elastic expansion sleeves 3, 8 (Fig. 2) with tapered surfaces cooperate with the tapered surfaces of the mandrel body 1, the double cone 5, and the outer sleeve 10, respectively, and are assembled as shown. As long as it is used in the forward rotation