Bearing tolerance symbols

The bearing tolerance symbols are a list of codes and bymbols which used in the bearing tolerance tables. However, in some cases the code or symbol definition has been abbreviated.

The symbols normally refer to dimensional tolerances, only Kia, Kea, Sd, SD, Sia and Sea refer to geometrical tolerances, which include tolerances of run-out and orientation.

Bearing tolerance symbols
Symbol	Definition
Radial bearings - inner ring, cylindrical and tapered bore
d	Cylindrical bore: Nominal bore diameter Tapered bore: Nominal bore diameter at the theoretical small end
Δdmp	Cylindrical bore: Deviation of a mid-range size (out of two-point sizes) of bore diameter in any cross section from its nominal size Tapered bore: Deviation of a mid-range size (out of two-point sizes) of bore diameter at the theoretical small end from its nominal size
Vdsp	Range of two-point sizes of bore diameter in any cross section of a cylindrical or tapered bore
Vdmp	Range of mid-range sizes (out of two-point sizes) of bore diameter obtained from any cross section of a cylindrical bore
B	Nominal inner ring width
ΔBs Normal, Modified ⁽¹⁾	Symmetrical rings: Deviation of a two-point size of inner ring width from its nominal size Asymmetrical rings, upper limit: Deviation of a minimum circumscribed size of inner ring width, between two opposite lines, in any longitudinal section which includes the inner ring bore axis, from its nominal size Asymmetrical rings, lower limit: Deviation of a two-point size of inner ring width from its nominal size
VBs	Symmetrical rings: Range of two-point sizes of inner ring width Asymmetrical rings: Range of minimum circumscribed sizes of inner ring width, between two opposite lines, obtained from any longitudinal section which includes the inner ring bore axis
Kia ⁽⁴⁾	Circular radial run-out of inner ring bore surface of assembled bearing with respect to datum, i.e. axis, established from the outer ring outside surface
Sd ⁽⁴⁾	Circular axial run-out of inner ring face with respect to datum, i.e. axis, established from the inner ring bore surface
Sia ⁽⁴⁾	Circular axial run-out of inner ring face of assembled bearing with respect to datum, i.e. axis, established from the outer ring outside surface
Radial bearings - inner ring, tapered bore only
d1	Nominal bore diameter at the theoretical large end of a tapered bore
Δd1mp	Deviation of a mid-range size (out of two-point sizes) of bore diameter at the theoretical large end from its nominal size
SL	Taper slope, the difference between nominal diameters at the theoretical large end and small end of a tapered bore (d1 - d)
ΔSL	Deviation of taper slope of a tapered inner ring bore from its nominal size
Radial bearings - outer ring
D	Nominal outside diameter
ΔDmp	Deviation of a mid-range size (out of two-point sizes) of outside diameter in any cross section from its nominal size
VDsp	Range of two-point sizes of outside diameter in any cross section
VDmp	Range of mid-range sizes (out of two-point sizes) of outside diameter obtained from any cross section
C	Nominal outer ring width
ΔCs Normal, Modified ⁽¹⁾	Symmetrical rings: Deviation of a two-point size of outer ring width from its nominal size Asymmetrical rings, upper limit: Deviation of a minimum circumscribed size of outer ring width, between two opposite lines, in any longitudinal section which includes the outer ring outside surface axis, from its nominal size Asymmetrical rings, lower limit: Deviation of a two-point size of outer ring width from its nominal size
VCs	Symmetrical rings: Range of two-point sizes of outer ring width Asymmetrical rings: Range of minimum circumscribed sizes of outer ring width, between two opposite lines, obtained from any longitudinal section which includes the outer ring outside surface axis
Kea ⁽⁴⁾	Circular radial run-out of outer ring outside surface of assembled bearing with respect to datum, i.e. axis, established from the inner ring bore surface
SD ⁽⁴⁾	Perpendicularity of outer ring outside surface axis with respect to datum established from the outer ring face
Sea ⁽⁴⁾	Circular axial run-out of outer ring face of assembled bearing with respect to datum, i.e. axis, established from the inner ring bore surface
Chamfer limits
rs	Single chamfer dimension
rs min	Smallest single chamfer dimension of rs, r1, r2, r3, r4 …
r1, r3	Radial direction chamfer dimensions
r2, r4	Axial direction chamfer dimensions
Tapered roller bearings
T	Nominal assembled bearing width
ΔTs	Deviation of minimum circumscribed size of assembled bearing width from its nominal size
T1	Nominal effective width of cone (inner ring, with roller and cage assembly) assembled with a master cup (outer ring)
T2	Nominal effective width of cup assembled with a master cone
ΔT1s	Deviation of minimum circumscribed size of effective width (cone assembled with a master cup) from its nominal size
ΔT2s	Deviation of minimum circumscribed size of effective width (cup assembled with a master cone) from its nominal size
Thrust bearings - shaft washer
d	Nominal bore diameter of shaft washer, single direction bearing
Δdmp	Deviation of a mid-range size (out of two-point sizes) of shaft washer bore diameter in any cross section from its nominal size
Vdsp	Range of two-point sizes of shaft washer bore diameter in any cross section
d2	Nominal bore diameter of central shaft washer, double direction bearing
Δd2mp	Deviation of a mid-range size (out of two-point sizes) of central shaft washer bore diameter in any cross section from its nominal size
Vd2sp	Range of two-point sizes of central shaft washer bore diameter in any cross section
Si	Range of two-point sizes of thickness between shaft washer raceway and the back face, cylindrical roller thrust bearing Range of minimum spherical sizes between the raceway and the opposite back face of the shaft washer, obtained from any longitudinal section which includes the shaft washer bore axis, thrust ball bearing
Thrust bearings - housing washer
D	Nominal outside diameter of housing washer
ΔDmp	Deviation of a mid-range size (out of two-point sizes) of housing washer outside diameter in any cross section from its nominal size
VDsp	Range of two-point sizes of housing washer outside diameter in any cross section
Se	Range of two-point sizes of thickness between housing washer raceway and the back face, cylindrical roller thrust bearing Range of minimum spherical sizes between the raceway and the opposite back face of the housing washer, obtained from any longitudinal section which includes the housing washer outside surface axis, thrust ball bearing
Thrust bearings - assembled bearing height
T	Nominal assembled bearing height, single direction thrust bearing (except spherical roller thrust bearing → T4)
ΔTs	Deviation of minimum circumscribed size of assembled bearing height from its nominal size, single direction thrust bearing (except spherical roller thrust bearing → ΔT4s)
T1	Nominal assembled bearing height, double direction thrust bearing Nominal assembled bearing height, single direction thrust bearing with a seat washer
ΔT1s	Deviation of minimum circumscribed size of assembled bearing height from its nominal size, double direction thrust bearing Deviation of minimum circumscribed size of assembled bearing height from its nominal size, single direction thrust bearing with a seat washer
T3 ⁽²⁾	Nominal assembled bearing height, double direction thrust bearing with seat washers
ΔT3s ⁽²⁾	Deviation of minimum circumscribed size of assembled bearing height from its nominal size, double direction thrust bearing with seat washers
T4 ⁽³⁾	Nominal assembled bearing height, spherical roller thrust bearing
ΔT4s ⁽³⁾	Deviation of minimum circumscribed size of assembled bearing height from its nominal size, spherical roller thrust bearing

(1) Modified applies to inner rings and outer rings of bearings of matched bearing sets consisting of two or more bearings. Does not apply to universally matchable angular contact ball bearings.
(2) Not included in ISO 199.
(3) In ISO 199, the symbol T is used.
(4) Geometrical tolerances

Technical information