I designed this for a friend that needed to put up temporary high tensile electric fence for cattle. It fits the esun spools best. not sure about others at this point. 

Parts I used:

2 608 2rs bearings

5/16 x 3" round head square shank bolt( I'm not really sure what they are called…), and lock nut

3/8 x 6" bolt and lock nut

2x m4x12 socket cap screws 

4x m4x16 socket cap screws

Washers are optional, but not really needed.