Ibbotson's patent lock nut (2 saw cut across top) viz:- 1 nut 1" diam

Ibbotson's patent lock nut (2 saw cut across top) viz:- 1 nut 1" diam; 2 bolts 3 1/4" long on one head, 3/4" diam

Two forms of this nut are shown, but the action is the same in both cases. The nut is similar to that of Halpin, but has two saw-cuts instead of one. This form of lock nut has been extensively adopted for permanent way, but to prevent the formation of rust in the saw-cuts it has been found well to fill them up with thick grease.