Ned: There is an adjustment nut with a tabbed washer that is bent into the
nut to lock it down once adjusted.
thanks, John

Is there a single tapered roller bearing at each end of the shaft or
two tapered bearings together or what arrangement? Whatever you
determine the force to be, be sure to rotate the bearing several
rotations in each direction as you tighten the nut to allow the
rollers to align properly. Otherwise, they will align once they start
running and change the preload.