Tolerances for super precision bearings conform to DIN 620. Dimensions and precision are defined in DIN ISO 1132. In order to ensure the full use of the performance of the bearing and achieve very high machining accuracy, the size, shape and running accuracy of FAG super-precision bearings are manufactured according to the small tolerances set in the standard: the shape and position tolerances also conform to the corresponding accuracy level. All super precision spindle bearings and floating displacement bearings reach P2 grade, except for B718 series, which reach P4 grade UP grade precision cylindrical roller bearings. Bore diameter measurement method d u003d nominal bore diameter (conical bore: minimum diameter) d1 u003d nominal diameter of the large end of the tapered bore ds u003d ds d in a single radial plane, deviation of a single diameter from the nominal diameter dmp u003d dmp d in a single radial In-plane, deviation of mean bore diameter from nominal bore diameter d1mp u003d d1mp d1 Deviation of the mean diameter of the large end of the tapered bore from the nominal bore diameter Vdp u003d dpsmax dpsmin Variation of a single bore diameter in a single radial plane (Vdp is approximately out of roundness, according to DIN 620) ; (Vdp/2 is approximately roundness according to DIN ISO 1132) (measurement method is equivalent to the measurement of out-of-roundness) Vdmp u003d dmpmax dmpmin Variation of the mean pore diameter in different radial planes. Outer diameter measurement method D u003d Nominal outer diameter Ds u003d Ds D In a single radial plane, the deviation of the single outer diameter from the nominal outer diameter Dmp u003d Dmp D In a single radial plane, the deviation of the average outer diameter from the nominal outer diameter VDp u003d Dpsmax DpsminV Variation of outer diameter in a single radial plane (VDp equivalent to out-of-roundness according to DIN 620); (VDp/2 equivalent to roundness according to DIN ISO 1132) (measurement method equivalent to measurement of out-of-roundness )VDmp u003d Dmpmax Dmpmin average outer diameter variation in different radial planes. Width and height measurement method Bs u003d Bs B Deviation between single inner ring width and nominal width Cs u003d Cs C Deviation between single outer ring width and nominal width VBs u003d Bsmax Bsmin Variation in inner ring width VCs u003d Csmax Csmin Variation in outer ring width Quantity Hs u003d Hs H Deviation of the height of a single complete set of thrust bearings from the nominal height. Running accuracy measurement method Kia u003d Radial runout of the inner ring of the bearing set Kea u003d Radial runout of the outer ring of the bearing set Sd u003d Runout of the end face of the inner ring relative to the inner hole (axial runout) SD u003d Cylindrical surface of the outer ring relative to the reference surface of the outer ring The amount of inclination variation (axial runout). Sia u003d End runout (axial runout) of the inner ring of the complete bearing set relative to the inner ring raceway Axial runout of thrust bearing) Se u003d Wall thickness variation of thrust bearing race (axial runout of thrust bearing).