the hollow shaft 10 to prevent any relative rotation between the stationary supports 5 a 5 b and the hollow shaft 10 if the rigidity of the stationary supports 5 a 5 b is insufficient additional structure may be used to minimize any relative rotational movement or flexing of the stationary supports 5 a 5 b this type of movement by the stationary supports 5 a 5 b may cause binding of the spindle rollers 4 a u2013 f as they move along the grooves 6 a u2013 f as shown in fig4 and 7 the additional structure may take the form of spacers 8 a 8 b 8 c attached between the stationary supports 5 a 5 b the spacers 8 a 8 b 8 c add rigidity between the stationary supports 5 a 5 b and in one embodiment are located near the outer circumference of the stationary supports 5 a 5 b in one embodiment the stationary supports 5 a 5 b are connected to the spacers 8 a 8 b 8 c by bolts or other fastener devices 45 a u2013 f inserted through holes 46 a u2013 f in the stationary supports 5 a 5 b referring.