Timken Super Precision Bearings for Machine Tool Applications

TOLERANCES
TAPERED ROLLER BEARINGS
Tapered roller bearings are manufactured to a number of
specifications or “classes” that define tolerances on dimensions
such as bore, O.D., width and runout. The Timken Company produces
bearings in both inch and metric systems. The boundary dimension
tolerances applicable to these two categories of bearings differ.
Metric
Inch
System bearing type
Precision bearing class
Tapered roller bearings C B A AA
Timken
Crossed roller bearings S P - -
ISO/DIN Tapered roller bearings P5 P4 P2 -
ABMA Tapered roller bearings C B A -
Tapered roller bearings 3 0 00 000
Timken
Crossed roller bearings 3 0 - -
ABMA Tapered roller bearings 3 0 00 -
Table 17. Tapered roller bearing precision classes.
ENGINEERING
The major difference between the two tolerance systems is that inch
bearings have historically been manufactured to positive bore and
O.D. tolerances, whereas metric bearings have been manufactured
to negative tolerances.
METRIC SYSTEM BEARINGS
(ISO AND “J” PREFIX PARTS)
Timken manufactures metric system bearings to four tolerance
classes. Classes C, B, A and AA are “precision” classes. These
tolerances lie within those currently specified in ISO 492 with
the exception of a small number of dimensions indicated in the
tables. The differences normally have an insignificant effect on
the mounting and performance of tapered roller bearings.
The adjacent table illustrates the current ISO bearing class that
corresponds approximately to each of The Timken Company metric
bearing classes.
A
Bearing
types (1)
TS
TSF
Cone bore
Bore
Over Incl.
mm
in.
mm
in.
Metric bearing tolerances
Precision bearing class
C B A AA
Max. Min. Max. Min. Max. Min. Max. Min.
mm
in.
mm
in.
mm
in.
10.000 18.000 0.000 -0.007 0.000 -0.005 0.000 -0.005 0.000 -0.005
0.3937 0.7087 0.0000 -0.0002 0.0000 -0.0001 0.0000 -0.0001 0.0000 -0.0001
18.000 30.000 0.000 -0.008 0.000 -0.006 0.000 -0.006 0.000 -0.006
0.7087 1.1811 0.0000 -0.0003 0.0000 -0.0002 0.0000 -0.0002 0.0000 -0.0002
30.000 50.000 0.000 -0.010 0.000 -0.008 0.000 -0.008 0.000 -0.008
1.1811 1.9685 0.0000 -0.0004 0.0000 -0.0003 0.0000 -0.0003 0.0000 -0.0003
50.000 80.000 0.000 -0.012 0.000 -0.009 0.000 -0.008 0.000 -0.008
1.9685 3.1496 0.0000 -0.0005 0.0000 -0.0004 0.0000 -0.0003 0.0000 -0.0003
80.000 120.000 0.000 -0.015 0.000 -0.010 0.000 -0.008 0.000 -0.008
3.1496 4.7244 0.0000 -0.0006 0.0000 -0.0004 0.0000 -0.0003 0.0000 -0.0003
120.000 180.000 0.000 -0.018 0.000 -0.013 0.000 -0.008 0.000 -0.008
4.7244 7.0866 0.0000 -0.0007 0.0000 -0.0005 0.0000 -0.0003 0.0000 -0.0003
180.000 250.000 0.000 -0.022 0.000 -0.015 0.000 -0.008 0.000 -0.008
7.0866 9.8425 0.0000 -0.0009 0.0000 -0.0006 0.0000 -0.0003 0.0000 -0.0003
250.000 265.000 0.000 -0.022 0.000 -0.015 0.000 -0.008 0.000 -0.008
9.8425 10.4331 0.0000 -0.0009 0.0000 -0.0006 0.0000 -0.0003 0.0000 -0.0003
265.000 315.000 0.000 -0.022 0.000 -0.015 0.000 -0.008 0.000 -0.008
10.4331 12.4016 0.0000 -0.0009 0.0000 -0.0006 0.0000 -0.0003 0.0000 -0.0003
315.000 400.000 0.000 -0.025 – – – – – –
12.4016 15.7480 0.0000 -0.0010 – – – – – –
400.000 500.000 0.000 -0.025 – – – – – –
15.7480 19.6850 0.0000 -0.0010 – – – – – –
500.000 630.000 0.000 -0.030 – – – – – –
19.6850 24.8031 0.0000 -0.0012 – – – – – –
630.000 800.000 0.000 -0.040 – – – – – –
24.8031 31.4961 0.0000 -0.0014 – – – – – –
800.000 1000.000 0.000 -0.050 – – – – – –
31.4961 39.3701 0.0000 -0.0020 – – – – – –
1000.000 1200.000 0.000 -0.060 – – – – – –
39.3701 47.2441 0.0000 -0.0024 – – – – – –
1200.000 1600.000 0.000 -0.080 – – – – – –
47.2441 62.9921 0.0000 -0.0031 – – – – – –
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
(1) Not all types and sizes are listed in this catalog. Contact your Timken representative for further information.
TIMKEN MACHINE TOOL CATALOG 67