Bearing Tolerances (Metric and Inch) Definition

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The Tolerance Tables found on the following pages covering bearings stocked by Consolidated conform to the American Bearing Manufacturers Association (ABMA) and the International Standards Organization (ISO) standards. However, tolerance standards have not been established for Needle Roller Bearings, Spherical Plain Bearings and Linear Recirculating Ball Bearings by either ABMA or ISO.These bearings are available in Tolerance Classes, STANDARD (ABEC-1) (no markings), P/6 (ABEC-3), P/5 (ABEC-5) and P/4 (ABEC-7). Bearings in Tolerance Classes P/5 (ABEC-5) and P/4 (ABEC-7), P/4S (ABEC-7 with ABEC-9 ) running accuracies are ideal for special applications such as machine tool spindles.


Our inch series of bearings are available in Standard (ABEC-1) and P/6 (ABEC-3) with tolerance classes for external dimension limits and running accuracy.
To clarify the headings and symbols used in these Tolerance Tables, the following definitions will apply.

d = Nominal bearing bore diameterdm = Bore Tolerances for all bearings within specific bore diameters

D = Nominal bearing outside diameter

Dm = Outside Diameter Tolerances for all bearings within specific O.D. diameters.

B = Width of bearing

T = Overall bearing width of Tapered Roller Bearings

Radial Runout =

Inner Ring: The radial runout of a radial bearing is the difference between the maximum and minimum indicator readings taken on the bore while rotating the inner ring one revolution.Outer Ring: The radial runout of a radial bearing outer ring is the difference between the minimum and maximum reading when rotating the outer ring one revolution with arbor stationary.

Axial Runout = Thrust Bearings - Maximum variation of shaft or housing washer thickness.

H = Bearing height - Thrust Bearings.