When a compressive axial load is applied in a slenderness ratio ballscrew which are long as small diameter the screw may fail due to buckling, before reaching the static load capacity Coam. The static load is which a screw can support on the ball zone with its ball track of screw and nut, and the compressive column load is of the screw itself. This load that a screw can support depends upon its diameter, length between supports, and type of supports at the ends journals.

To determine this data the column load graphic shows us the values for each type of assembly, with two variables: diameter of the screw and length between supports. The safety coefficient for this development has been introduced in this graphic.

In this graphic we have shown as an example, a ballscrew diameter do 63 mm with a Lar length between supports of 5 m.
The allowable column load Fka that we obtain, according to the selected supports is of 4,7 – 18,8 – 37,6 and 75,2 KN respectively.