Flange bushings are sleeve type bearings with a “flange” or “shoulder” on one end. The flange serves multiple functions. It can assist in alignment and mounting of the bearing. It can also help ease installation of the bearing. The flange bushing has 5 distinctive parts.
Essentially, Flange Bushings are used to replace larger bolts with smaller bolts, as, in most Spar applications, it is not the tensile strength of the bolt, but the increase in shear strength gained by the larger bearing surface that is important.