The chuck Spider allows adjustment between the spindle center and the work center in all three axises. An 8.5 degree turn of an adjusting screw moves the chuck 0.001 thousandth of an inch. So, fine adjustment is not at all difficult. It does not take but a few thousandths of an inch run out anywhere in the Rose Engine system, from the cam to the workpiece, to show in delicate cuts.
Brass tipped set screws are used to keep from damaging the adjustment surfaces of the Spider and ensuring smooth adjustments.