SINGLE NUT WITH FLANGE Type: KBS • Standard thread RH only. Left-hand thread on request. • Rs1= Rigidity of the ball screw shaft with one end fixed and one end free, per unit length of one metre. For two-end fixed systems, multiply by 4. • Rnu = Rigidity of the nut for a working load equal to 30% of the dynamic load rating and for a tolerance grade of IT5.