The accuracy of a ball screw is controlled in accordance with Japanese Industrial Standards. (JIS B 1997-1192) These standards relate to the tolerance of specified travel, and three different measurements of travel variation.
NSK use the C and Ct type specification.
The C system is used for higher accuracy “positioning” applications, Ct is for “transport” applications where high accuracy is not required. In both systems the lower the number the more accurate the ball screw.
NSK precision ground ball screws as standard have a lead accuracy rating from C3 to C5. They have also been designed with zero Axial play resulting is no backlash.
Some other manufactures offer considerably cheaper alternative ball screws but they can rarely match the C5 Accuracy of standard NSK Ground ball screws. If accuracy is important to your application then the difference in cost is more than made up with the guaranteed accuracy offered by NSK.
MA, SA, FA and compact fa pss type
Precision Ground C5 Accuracy
Preloaded, Zero Axial Play, No Backlash
High Accuracy and Rigidity
Machine Finished Ends
Image courtesy of NSK
finished shaft ends
The MA, SA, FA and compact FA PSS precision Ball screws have machined finished ends to fit directly onto NSK support unit’s
Image courtesy of NSK
lpr / PR VSp series
Precision Rolled Ct5-Ct7 Accuracy
Preloaded for minimum Axial Play and no Backlash
Suitable for High Speed and Long Stroke Applications
RMS / RMA Series
Miniature versions of precision rolled ball screws are available in the RMS / RMA series with screw diameters of 6 - 12mm. These are available with blank shaft ends or machine finished ends suitable for support units.
Precision Rolled Ct7 Accuracy
Non preload
Slight Axial Play
Suitable for transporting Equipment
R Series
Designed exclusively for transport equipment where high accuracy is not important the R series is ideal with its more competitive pricing. Available in screw diameters ranging from 10 - 50mm and larger screw shaft diameters available up to 4000 mm long.
Ct10 Accuracy
Non preload
Slight Axial Play
Non Machined Ends
Range of different shaped nuts including: RNFTL - Flanged, external recirculation return tube, RNFBL - Flanged, internal recirculation return tube, RNFCL - Flanged, internal recirculation end cap, RNSTL - Square, external recirculation return tube and RNCT - No flange, with v thread, external recirculation return tub.