Shaft support blocks are used for end or intermittent support where loads are light and slight shaft deflection is not a concern.  Unlike shaft support rails, blocks do not permit longitudinal passage of open-type ball bushing bearings.  Shaft support blocks enable clamping of shafts, type SB and eliminate the need for bolts to maintain shaft position.  Shimming is suggested for high precision applications to eliminate the effect of variations in surface of base or manufacturing tolerances between supports.