Hardinge R8 Round Smooth Small Hole Collet, 1/64" Hole Size Collet for holding workpieces in a lathe or other machine tool Size R8 round smooth collet with a through-capacity of 3/4 inch Back bearing diameter of 15/16 inch and overall length of 4 inches Heat-treated right-hand 0.437 inch x 20 external threads for long life Hardened and ground spring steel for accuracy and resistance to wear and breakage