Bores and Keyways
In the following section you will find information on British standard keyway and bore sizes. Precision Chains will generally bore all wheels to a H7 tolerance unless specified by the customer. All wheels will come with grub screw fixings over keyways and at 90 degrees as standard. The standard positioning for all keyways will be in line with a tooth.
It is important to remember that on twin stranded conveyors and elevators where matched chains are used it is equally important that matched wheels are specified since this involves careful keyway cutting to ensure both wheels engage the wheel at exactly the same time. In the case of tail wheels on twin strand elevators one wheel should be keyed to the shaft and the other should run loose to compensate for any uneven strand lengths that may develop over time.
Wheels can be supplied with alternatives to keyways and plain bores such as oilite bushes, phosphor bronze bushes, plastic bushes, clamping elements and weld on hubs for use with taper lock bushes.
H7 bore tolerances
|
Unit |
Nominal hole sizes |
|||||||||||
|
Over |
[mm] |
3 |
6 |
10 |
18 |
30 |
50 |
80 |
120 |
180 |
250 |
315 |
|
Up to and including |
[mm] |
6 |
10 |
18 |
30 |
50 |
80 |
120 |
180 |
250 |
315 |
400 |
|
H7 |
[µm] |
+12 0 |
+15 0 |
+18 0 |
+21 0 |
+25 0 |
+30 0 |
+35 0 |
+40 0 |
+46 0 |
+52 0 |
+57 0 |
The following tables show standard
dimensions for keys and their grooves.
Imperial – Rectangular B.S.46:PART 1:1958
|
D |
W x T |
W |
H |
W |
h |
W |
T |
R |
||
|
Shaft Diameter |
||||||||||
|
Over |
Up to (inc.) |
Key |
Keyway in shaft |
Keyway in hub |
Keybar |
Radius |
||||
|
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
|
|
1 |
1 1/4 |
5/16 x 1/4 |
Min. |
0.311 |
0.146 |
0.312 |
0.112 |
0.314 |
0.253 |
0.010 |
|
Max. |
0.312 |
0.152 |
0.313 |
0.118 |
0.312 |
0.250 |
||||
|
1 1/4 |
1 1/2 |
3/8 x 1/4 |
Min. |
0.374 |
0.150 |
0.375 |
0.108 |
0.377 |
0.253 |
0.010 |
|
Max. |
0.375 |
0.156 |
0.376 |
0.114 |
0.375 |
0.250 |
||||
|
1 1/2 |
1 3/4 |
7/16 x 5/16 |
Min. |
0.437 |
0.186 |
0.438 |
0.135 |
0.440 |
0.315 |
0.020 |
|
Max. |
0.438 |
0.192 |
0.439 |
0.141 |
0.438 |
0.312 |
||||
|
1 3/4 |
2 |
1/2 x 5/16 |
Min. |
0.499 |
0.190 |
0.500 |
0.131 |
0.502 |
0.315 |
0.020 |
|
Max. |
0.500 |
0.196 |
0.501 |
0.137 |
0.500 |
0.312 |
||||
|
2 |
2 1/2 |
5/8 x 7/16 |
Min. |
0.624 |
0.260 |
0.625 |
0.185 |
0.627 |
0.441 |
0.020 |
|
Max. |
0.625 |
0.266 |
0.626 |
0.191 |
0.625 |
0.438 |
||||
|
2 1/2 |
3 |
3/4 x 1/2 |
Min. |
0.749 |
0.299 |
0.750 |
0.209 |
0.752 |
0.503 |
0.020 |
|
Max. |
0.750 |
0.305 |
0.751 |
0.215 |
0.750 |
0.500 |
||||
|
3 |
3 1/2 |
7/8 x 5/8 |
Min. |
0.874 |
0.370 |
0.875 |
0.264 |
0.877 |
0.629 |
0.062 |
|
Max. |
0.875 |
0.376 |
0.876 |
0.270 |
0.875 |
0.625 |
||||
|
3 1/2 |
4 |
1 x 3/4 |
Min. |
0.999 |
0.441 |
1.000 |
0.318 |
1.003 |
0.754 |
0.062 |
|
Max. |
1.000 |
0.447 |
1.001 |
0.324 |
1.000 |
0.750 |
||||
|
4 |
5 |
1 1/4 x 7/8 |
Min. |
1.248 |
0.518 |
1.250 |
0.366 |
1.253 |
0.879 |
0.062 |
|
Max. |
1.250 |
0.524 |
1.252 |
0.372 |
1.250 |
0.875 |
||||
|
5 |
6 |
1 1/2 x 1 |
Min. |
1.498 |
0.599 |
1.500 |
0.412 |
1.504 |
1.006 |
0.062 |
|
Max. |
1.500 |
0.605 |
1.502 |
0.418 |
1.500 |
1.000 |
||||
Metric – Rectangular B.S.4235:PART 1:1972
|
D |
W x T |
W |
H |
W |
h |
W |
T |
R |
||
|
Shaft Diameter |
||||||||||
|
Over |
Up to (inc.) |
Key |
Keyway in shaft |
Keyway in hub |
Keybar |
Radius |
||||
|
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
|
|
10 |
12 |
4 x 4 |
Min. |
3.970 |
2.5 |
3.985 |
1.8 |
4.030 |
0.16 |
|
|
Max. |
4.000 |
2.6 |
4.015 |
1.9 |
3.970 |
|||||
|
12 |
17 |
5 x 5 |
Min. |
4.970 |
3.0 |
4.985 |
2.3 |
5.030 |
0.25 |
|
|
Max. |
5.000 |
3.1 |
5.015 |
2.4 |
4.970 |
|||||
|
17 |
22 |
6 x 6 |
Min. |
5.970 |
3.5 |
5.985 |
2.8 |
6.030 |
0.25 |
|
|
Max. |
6.000 |
3.6 |
6.015 |
2.9 |
5.970 |
|||||
|
22 |
30 |
8 x 7 |
Min. |
7.964 |
4.0 |
7.982 |
3.3 |
8.000 |
7.000 |
0.25 |
|
Max. |
8.000 |
4.2 |
8.018 |
3.5 |
7.964 |
6.910 |
||||
|
30 |
38 |
10 x 8 |
Min. |
9.964 |
5.0 |
9.982 |
3.3 |
10.000 |
8.000 |
0.40 |
|
Max. |
10.000 |
5.2 |
10.018 |
3.5 |
9.964 |
7.910 |
||||
|
38 |
44 |
12 x 8 |
Min. |
11.957 |
5.0 |
11.979 |
3.3 |
12.000 |
8.000 |
0.40 |
|
Max. |
12.000 |
5.2 |
12.021 |
3.5 |
11.957 |
7.910 |
||||
|
44 |
50 |
14 x 9 |
Min. |
13.957 |
5.5 |
13.979 |
3.8 |
14.000 |
9.000 |
0.40 |
|
Max. |
14.000 |
5.7 |
14.021 |
4.0 |
13.957 |
8.910 |
||||
|
50 |
58 |
16 x 10 |
Min. |
15.957 |
6.0 |
15.979 |
4.3 |
16.000 |
10.000 |
0.40 |
|
Max. |
16.000 |
6.2 |
16.021 |
4.5 |
15.957 |
9.910 |
||||
|
58 |
65 |
18 x 11 |
Min. |
17.957 |
7.0 |
17.979 |
4.4 |
18.000 |
11.000 |
0.40 |
|
Max. |
18.000 |
7.2 |
18.021 |
4.6 |
17.957 |
10.890 |
||||
|
65 |
75 |
20 x 12 |
Min. |
19.948 |
7.5 |
19.974 |
4.9 |
20.000 |
12.000 |
0.60 |
|
Max. |
20.000 |
7.7 |
20.026 |
5.1 |
19.948 |
11.890 |
||||
|
75 |
85 |
22 x 14 |
Min. |
21.948 |
9.0 |
21.974 |
5.4 |
22.000 |
14.000 |
0.60 |
|
Max. |
22.000 |
9.2 |
22.026 |
5.6 |
21.948 |
13.890 |
||||
|
85 |
95 |
25 x 14 |
Min. |
24.948 |
9.0 |
24.974 |
5.4 |
25.000 |
14.000 |
0.60 |
|
Max. |
25.000 |
9.2 |
25.026 |
5.6 |
24.948 |
13.890 |
||||
|
95 |
110 |
28 x 16 |
Min. |
27.948 |
10.0 |
27.974 |
6.4 |
28.000 |
16.000 |
0.60 |
|
Max. |
28.000 |
10.2 |
28.026 |
6.6 |
27.948 |
15.890 |
||||
|
110 |
130 |
32 x 18 |
Min. |
31.938 |
11.0 |
31.969 |
7.4 |
32.000 |
18.000 |
0.60 |
|
Max. |
32.000 |
11.2 |
32.031 |
7.6 |
31.938 |
17.890 |
||||
|
130 |
150 |
36 x 20 |
Min. |
35.938 |
12.0 |
35.969 |
8.4 |
36.000 |
20.000 |
1.00 |
|
Max. |
36.000 |
12.3 |
36.031 |
8.7 |
35.938 |
19.870 |
||||
|
150 |
170 |
40 x 22 |
Min. |
39.938 |
13.0 |
39.969 |
9.4 |
40.000 |
22.000 |
1.00 |
|
Max. |
40.000 |
13.3 |
40.031 |
9.7 |
39.938 |
21.870 |
||||
|
170 |
200 |
45 x 25 |
Min. |
44.938 |
15.0 |
44.969 |
10.4 |
45.000 |
25.000 |
1.00 |
|
Max. |
45.000 |
15.3 |
45.031 |
10.7 |
44.938 |
24.870 |
||||
|
200 |
230 |
50 x 28 |
Min. |
49.938 |
17.0 |
49.969 |
11.4 |
50.000 |
28.000 |
1.00 |
|
Max. |
50.000 |
17.3 |
50.031 |
11.7 |
49.938 |
27.870 |
||||
Imperial – Square B.S.46:PART 1:1958
|
D |
W x T |
W |
H |
W |
h |
W & T |
R |
||
|
Shaft Diameter |
|||||||||
|
Over |
Up to (inc.) |
Key |
Keyway in shaft |
Keyway in hub |
Keybar |
Radius |
|||
|
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
|
|
1/4 |
1/2 |
1/8 x 1/8 |
Min. |
0.124 |
0.072 |
0.125 |
0.060 |
0.127 |
0.010 |
|
Max. |
0.125 |
0.078 |
0.126 |
0.066 |
0.125 |
||||
|
1/2 |
3/4 |
3/16 x 3/16 |
Min. |
0.187 |
0.107 |
0.188 |
0.088 |
0.190 |
0.010 |
|
Max. |
0.188 |
0.113 |
0.189 |
0.094 |
0.188 |
||||
|
3/4 |
1 |
1/4 x 1/4 |
Min. |
0.249 |
0.142 |
0.250 |
0.115 |
0.252 |
0.010 |
|
Max. |
0.250 |
0.148 |
0.251 |
0.121 |
0.250 |
||||
|
1 |
1 1/4 |
5/16 x 5/16 |
Min. |
0.311 |
0.177 |
0.312 |
0.142 |
0.314 |
0.010 |
|
Max. |
0.312 |
0.183 |
0.313 |
0.148 |
0.312 |
||||
|
1 1/4 |
1 1/2 |
3/8 x 3/8 |
Min. |
0.374 |
0.213 |
0.375 |
0.169 |
0.377 |
0.010 |
|
Max. |
0.375 |
0.219 |
0.376 |
0.175 |
0.375 |
||||
|
1 1/2 |
1 3/4 |
7/16 x 7/16 |
Min. |
0.437 |
0.248 |
0.438 |
0.197 |
0.440 |
0.020 |
|
Max. |
0.438 |
0.254 |
0.439 |
0.203 |
0.438 |
||||
|
1 3/4 |
2 |
1/2 x 1/2 |
Min. |
0.499 |
0.283 |
0.500 |
0.224 |
0.502 |
0.020 |
|
Max. |
0.500 |
0.289 |
0.501 |
0.230 |
0.500 |
||||
|
2 |
2 1/2 |
5/8 x 5/8 |
Min. |
0.624 |
0.354 |
0.625 |
0.278 |
0.627 |
0.020 |
|
Max. |
0.625 |
0.360 |
0.626 |
0.284 |
0.625 |
||||
|
2 1/2 |
3 |
3/4 x 3/4 |
Min. |
0.749 |
0.424 |
0.750 |
0.333 |
0.752 |
0.020 |
|
Max. |
0.750 |
0.430 |
0.751 |
0.339 |
0.750 |
||||
|
3 |
3 1/2 |
7/8 x 7/8 |
Min. |
0.874 |
0.495 |
0.875 |
0.387 |
0.877 |
0.062 |
|
Max. |
0.875 |
0.501 |
0.876 |
0.393 |
0.875 |
||||
|
3 1/2 |
4 |
1 x 1 |
Min. |
0.999 |
0.566 |
1.000 |
0.442 |
1.003 |
0.062 |
|
Max. |
1.000 |
0.572 |
1.001 |
0.448 |
1.000 |
||||
|
4 |
5 |
1 1/4 x 1 1/4 |
Min. |
1.248 |
0.707 |
1.250 |
0.551 |
1.253 |
0.062 |
|
Max. |
1.250 |
0.713 |
1.252 |
0.557 |
1.250 |
||||
|
5 |
6 |
1 1/2 x 1 1/2 |
Min. |
1.498 |
0.848 |
1.500 |
0.661 |
1.504 |
0.062 |
|
Max. |
1.500 |
0.854 |
1.502 |
0.667 |
1.500 |
||||
Imperial – Rectangular Taper Keyways
|
D |
W & T |
W |
H |
W |
h |
R |
|||||
|
Shaft Diameter |
Key Size |
Keyway in shaft |
Keyway in hub |
Radius |
|||||||
|
Over |
Up to (inc.) |
Min. |
Max. |
Min. |
Max. |
Min. |
Max. |
Min. |
Max. |
||
|
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
[in] |
|
1/4 |
1/2 |
1/8 |
0.124 |
0.125 |
0.072 |
0.078 |
0.125 |
0.126 |
0.039 |
0.045 |
0.010 |
|
1/2 |
3/4 |
3/16 |
0.187 |
0.188 |
0.107 |
0.113 |
0.188 |
0.189 |
0.067 |
0.073 |
0.010 |
|
3/4 |
1 |
1/4 |
0.249 |
0.250 |
0.142 |
0.148 |
0.250 |
0.251 |
0.094 |
0.100 |
0.010 |
|
1 |
1 1/4 |
5/16 |
0.311 |
0.312 |
0.177 |
0.183 |
0.312 |
0.313 |
0.121 |
0.127 |
0.010 |
|
1 1/4 |
1 1/2 |
3/8 |
0.374 |
0.375 |
0.213 |
0.219 |
0.375 |
0.376 |
0.148 |
0.154 |
0.010 |
|
1 1/2 |
1 3/4 |
7/16 |
0.437 |
0.438 |
0.248 |
0.254 |
0.438 |
0.439 |
0.175 |
0.181 |
0.020 |
|
1 3/4 |
2 |
1/2 |
0.499 |
0.500 |
0.283 |
0.289 |
0.500 |
0.501 |
0.202 |
0.208 |
0.020 |
|
2 |
2 1/2 |
5/8 |
0.624 |
0.625 |
0.354 |
0.360 |
0.625 |
0.626 |
0.256 |
0.262 |
0.020 |
|
2 1/2 |
3 |
3/4 |
0.749 |
0.750 |
0.424 |
0.430 |
0.750 |
0.751 |
0.310 |
0.316 |
0.020 |
|
3 |
3 1/2 |
7/8 |
0.874 |
0.875 |
0.495 |
0.501 |
0.875 |
0.875 |
0.876 |
0.370 |
0.062 |
|
3 1/2 |
4 |
1 |
0.999 |
1.000 |
0.566 |
0.572 |
1.000 |
1.001 |
0.418 |
0.424 |
0.062 |
|
4 |
5 |
1 1/4 |
1.248 |
1.250 |
0.707 |
0.713 |
1.250 |
1.252 |
0.526 |
0.532 |
0.062 |
|
5 |
6 |
1 1/4 |
1.498 |
1.500 |
0.848 |
0.854 |
1.500 |
1.502 |
0.635 |
0.641 |
0.062 |
Metric – Rectangular Taper Keyways
|
D |
W x T |
W |
H |
h |
R |
|||||||||
|
Shaft diameter |
Key |
Keyway width (tolerance for class of fit) |
Keyway Depth shaft |
Keyway Depth hub |
Radius |
|||||||||
|
Over |
Up to (inc.) |
Nom. |
Free |
Free |
Normal |
Normal |
Close and |
Nom. |
Tol. |
Nom. |
Tol. |
Max. |
Min. |
|
|
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
[mm] |
|
22 |
30 |
8 x 7 |
8 |
+ 0.036 0 |
+ 0.098 + 0.040 |
0 – 0.036 |
+ 0 .018 – 0 .018 |
– 0.015 – 0.051 |
4 |
+ 0.2 0 |
3.3 |
+ 0.2 0 |
0.25 |
0.16 |
|
30 |
38 |
10 x 8 |
10 |
+ 0.036 0 |
+ 0.098 + 0.040 |
0 – 0.036 |
+ 0 .018 – 0 .018 |
– 0.015 – 0.051 |
5 |
+ 0.2 0 |
3.3 |
+ 0.2 0 |
0.40 |
0.25 |
|
38 |
44 |
12 x 8 |
12 |
+ 0.043 0 |
+ 0.120 + 0.050 |
0 – 0.043 |
+ 0.021 – 0.021 |
– 0.018 – 0.061 |
5 |
+ 0.2 0 |
3.3 |
+ 0.2 0 |
0.40 |
0.25 |
|
44 |
50 |
14 x 9 |
14 |
+ 0.043 0 |
+ 0.120 + 0.050 |
0 – 0.043 |
+ 0.021 – 0.021 |
– 0.018 – 0.061 |
5.5 |
+ 0.2 0 |
3.8 |
+ 0.2 0 |
0.40 |
0.25 |
|
50 |
58 |
16 x 10 |
16 |
+ 0.043 0 |
+ 0.120 + 0.050 |
0 – 0.043 |
+ 0.021 – 0.021 |
– 0.018 – 0.061 |
6 |
+ 0.2 0 |
4.3 |
+ 0.2 0 |
0.40 |
0.25 |
|
58 |
65 |
18 x 11 |
18 |
+ 0.043 0 |
+ 0.120 + 0.050 |
0 – 0.043 |
+ 0.021 – 0.021 |
– 0.018 – 0.061 |
7 |
+ 0.2 0 |
4.4 |
+ 0.2 0 |
0.40 |
0.25 |
|
65 |
75 |
20 x 12 |
20 |
+ 0.052 0 |
+ 0.149 + 0.065 |
0 – 0.052 |
+ 0.026 – 0.026 |
– 0.022 – 0.074 |
7.5 |
+ 0.2 0 |
4.9 |
+ 0.2 0 |
0.60 |
0.40 |
|
75 |
85 |
22 x 14 |
22 |
+ 0.052 0 |
+ 0.149 + 0.065 |
0 – 0.052 |
+ 0.026 – 0.026 |
– 0.022 – 0.074 |
9 |
+ 0.2 0 |
5.4 |
+ 0.2 0 |
0.60 |
0.40 |
|
85 |
95 |
25 x 14 |
25 |
+ 0.052 0 |
+ 0.149 + 0.065 |
0 – 0.052 |
+ 0.026 – 0.026 |
– 0.022 – 0.074 |
9 |
+ 0.2 0 |
5.4 |
+ 0.2 0 |
0.60 |
0.40 |
|
95 |
110 |
28 x 16 |
28 |
+ 0.052 0 |
+ 0.149 + 0.065 |
0 – 0.052 |
+ 0.026 – 0.026 |
– 0.022 – 0.074 |
10 |
+ 0.2 0 |
6.4 |
+ 0.2 0 |
0.60 |
0.40 |
|
110 |
130 |
32 x 18 |
32 |
+ 0.062 0 |
+ 0.180 + 0.080 |
0 – 0.062 |
+ 0.031 – 0.031 |
– 0.026 – 0.088 |
11 |
+ 0.2 0 |
7.4 |
+ 0.2 0 |
0.60 |
0.40 |
|
130 |
150 |
38 x 20 |
38 |
+ 0.062 0 |
+ 0.180 + 0.080 |
0 – 0.062 |
+ 0.031 – 0.031 |
– 0.026 – 0.088 |
12 |
+ 0.3 0 |
8.4 |
+ 0.3 0 |
1.00 |
0.70 |
|
150 |
170 |
40 x 22 |
40 |
+ 0.062 0 |
+ 0.180 + 0.080 |
0 – 0.062 |
+ 0.031 – 0.031 |
– 0.026 – 0.088 |
13 |
+ 0.3 0 |
9.4 |
+ 0.3 0 |
1.00 |
0.70 |
|
170 |
200 |
45 x 25 |
45 |
+ 0.062 0 |
+ 0.180 + 0.080 |
0 – 0.062 |
+ 0.031 – 0.031 |
– 0.026 – 0.088 |
15 |
+ 0.3 0 |
10.4 |
+ 0.3 0 |
1.00 |
0.70 |
|
200 |
230 |
50 x 28 |
50 |
+ 0.062 0 |
+ 0.180 + 0.080 |
0 – 0.062 |
+ 0.031 – 0.031 |
– 0.026 – 0.088 |
17 |
+ 0.3 0 |
11.4 |
+ 0.3 0 |
1.00 |
0.70 |
|
230 |
260 |
56 x 32 |
56 |
+ 0.074 0 |
+ 0.220 + 0.100 |
0 – 0.074 |
+ 0.037 – 0.037 |
– 0.032 – 0.106 |
20 |
+ 0.3 0 |
12.4 |
+ 0.3 0 |
1.60 |
1.20 |
|
260 |
290 |
63 x 32 |
63 |
+ 0.074 0 |
+ 0.220 + 0.100 |
0 – 0.074 |
+ 0.037 – 0.037 |
– 0.032 – 0.106 |
20 |
+ 0.3 0 |
12.4 |
+ 0.3 0 |
1.60 |
1.20 |
|
290 |
330 |
70 x 36 |
70 |
+ 0.074 0 |
+ 0.220 + 0.100 |
0 – 0.074 |
+ 0.037 – 0.037 |
– 0.032 – 0.106 |
22 |
+ 0.3 0 |
14.4 |
+ 0.3 0 |
1.60 |
1.20 |
|
330 |
380 |
80 x 40 |
80 |
+ 0.074 0 |
+ 0.220 + 0.100 |
0 – 0.074 |
+ 0.037 – 0.037 |
– 0.032 – 0.106 |
25 |
+ 0.3 0 |
15.4 |
+ 0.3 0 |
2.50 |
2.00 |
|
380 |
440 |
90 x 45 |
90 |
+0.087 0 |
+ 0.260 + 0.120 |
0 – 0.087 |
+ 0.043 – 0.043 |
– 0.037 – 0.124 |
28 |
+ 0.3 0 |
17.4 |
+ 0.3 0 |
2.50 |
2.00 |
|
440 |
500 |
100 x 50 |
100 |
+0.087 0 |
+ 0.260 + 0.120 |
0 – 0.087 |
+ 0.043 – 0.043 |
– 0.037 – 0.124 |
31 |
+ 0.3 0 |
19.5 |
+ 0.3 0 |
2.50 |
2.00 |