The S1 Series, available for medium and high-load applications, uses a double row of ball bearings on both sides of the guide. This increases the number of contact points between the raceway and guide, thus increasing rigidity and lowering noise. To further decrease friction and reduce noise, NSK uses retainers made of a porous synthetic resin, or so-called "molded oil." Simple concave retaining pieces made of the self-lubricating resin separate each ball bearing. The bearings now move against plastic spacers and have a larger contact area with them..
Test show the S1 guides have noise levels 6 dBA quieter than standard linear guides. The new guides could be used in electric wire-cutting discharge machines, scanners, pattern generators, and other applications that demand smooth motion, according to NSK.