Bearing Steel Ball Specification

The specification of bearing steel ball:

Diameter (d)

Diameter (d)

Inch

Millimeter

Inch

Millimeter
2
8.5
3/32
2.381
11/32
8.731
2.5
9
3
23/64
9.132
3.1
3/8
9.525
1/8
3.175
13/32
10.319
3.5
15/32
11.006
5/32
3.969
7/12
11.113
4
31/64
12.303
4.5
1/2
12.70
3/16
4.763
9/16
14.28
5
9/32
15.81
5.5
5/8
15.875
7/32
5.556
11/16
17.463
15/64
5.953
18
6
23/32
18.256
1/4
6.35
3/4
19.05
6.5
25/32
19.844
7
20
9/32
7.144
27/32
21.431
7.5
7/8
22.225
5/16
7.938
31/32
24.606
8
1
25.4
5/8
15.8750
1 3/4
44.4500
21/32
16.6688
45.0000
11/16
17.4625
1 7/8
47.6250
23/32
18.2562
50.0000
3/4
19.0500
2    
50.8000
13/16
20.6375
2 1/8
53.9750
7/8
22.2250
55.0000
29/32
23.0188
2 1/4
57.1500
15/16
23.8125
60.0000
1     
25.400 
2 3/8
60.3250
1 1/16
26.9875
2 1/2
63.5000
1 1/8
28.5750
65.0000
30     
2 3/4
69.8500
1 3/16
30.1625
70.0000
1 1/4
31.7500
75.0000
32     
3    
76.2000
1 5/16
33.3375
80.0000
34     
3 1/2
88.9000
1 3/8
34.9250
90.0000
35     
100.0000
Grade of tolerance and technology requirement
Grade
 Ball diameter variation Spherical deviation Ball surface roughness Ball diameter variation Basic diameter tolerance
Vdws ?Sph Ra Vdwl Tdn
Not exceed not over
um
10 0.25 0.25 0.025 0.5 *
16 0.4 0.4 0.032 0.8 *
20 0.5 0.5 0.05 1 *
28 0.7 0.7 0.05 1.5 *
40 1.0 1.0 0.08 2 *
60 1.5 1.5 0.10 3 *
100 2.5 2.5 0.125 5 ±12.5
200 5 5 0.2 10 ±25
500 13 13 * 25 ±50
1000 25 25 * 50 ±125