About the preload of the ball screw :

            There are 4 pre-tightening states of common screw, level P0 has gap and no pre-tightening; level P1 has no gap and slight pre-tightening; level P2 has no gap and 3 ~ 5% dynamic load pre-tightening; level P3 has no gap and 8 ~ 10 % dynamic load pre-tightening.

           Level P0 has gap, level P1 is backlash-free and slightly pre-tensioned. When the lead screw is placed vertically, the nut will rotate and drop due to gravity. Level P0 is fast slide down, and level P1 is slow slide down. Level P0 pre-tightening is generally suitable for ordinary industrial machinery or automated production lines with low accuracy, and the rotation is smooth, but there will be backlash in this state. Pre-tensioned above P1 is suitable for semicon-ductor or 3C electronic equipment industry with less shock vibration.

           Level P2 generally has 3 ~ 5% dynamic load pre-tightening, level P3 generally has 8 ~ 10% dynamic load pre-tightening. When the screw is placed vertically, the nut will not slide down. Level P2 manual force can be turned, and level P3 manual force needs a lot of force to turn slightly. These two types of pre-tightening are generally applicable to precision metal processing machine tools, such as machining centers, CNC lathes, CNC milling machines, CNC drilling machines, and so on. The nut is pre-loaded, so that the screw can maintain high precision and rigidity for a long time, and can withstand large shocks and vibrations.

Customer drawing and final processing drawing

Finished product 

Dimension re-measurement