[Hawiian Cadder]

If you are using .5 hex shafts I might consider turning them down to round where it goes through the tube, or making the slot 3/4 of an inch wide. As it is now, you have about 1/32 of an inch clearance between the slot and the axle when a flat is perpendicular to the slot, if your blocks are even slightly off, or if you powder coat, the axle might start rubbing on the tube.


Edit:
The link you posted is for the 3/8 hex bearing on andymark, I think that is why Chris assumed you were using 3/8 hex shafts,