Our Precision Pivot Assemblies are designed by Darrel Ralph. These precision pivot assemblies are for the advanced knifemaker who wants a SMOOTH action. The ream size is .1875. The bushing is fitted within .0002 to slip-fit the 3/16 stud. The bushing is made from hardened stainless steel. The two bushing barrel o.d.'s that we offer with our precision assembly system are .250 and .310. DRPPK3 = 3/16 Precision Pivot Assembly with .310 Bushing All KnifeKits.com pivots are heat treated for low wear.   (1 Package = 1 Pivot, 1 Screw and 1 Bushing)