| Number
of teeth* |
Pitch
diam |
Maximum
Outside diam |
Maximum
Bottom diam |
| act. |
eff. |
in. |
mm |
in. |
mm |
in. |
mm |
12
13
14
15 |
6
6 1/2
7
7 1/2 |
3.000
3.228
3.457
3.688 |
76.20
81.99
87.81
93.68 |
2.848
3.108
3.365
3.619 |
72.34
78.94
85.47
91.92 |
2.475
2.703
2.932
3.163 |
62.87
68.66
74.47
80.34 |
16
17
18
19 |
8
8 1/2
9
9 1/2 |
3.920
4.152
4.386
4.620 |
99.57
105.46
111.40
117.35 |
3.871
4.122
4.371
4.620 |
98.32
104.7
111.02
117.35 |
3.395
3.627
3.861
4.095 |
86.23
92.13
98.07
104.01 |
20
21
22
23 |
10
10 1/2
11
11 1/2 |
4.854
5.089
5.324
5.560 |
123.29
129.26
135.23
141.22 |
4.854
5.089
5.324
5.560 |
123.29
129.26
135.23
141.22 |
4.329
4.564
4.799
5.035 |
109.96
115.93
121.89
127.89 |
24
25
26
27 |
12
12 1/2
13
13 1/2 |
5.796
6.032
6.268
6.504 |
147.22
153.21
159.21
165.20 |
5.796
6.032
6.268
6.504 |
147.22
153.21
159.21
165.20 |
5.271
5.507
5.743
5.979 |
133.88
139.88
145.87
151.87 |
28
29
30
31 |
14
14 1/2
15
15 1/2 |
6.741
6.978
7.215
7.452 |
171.22
177.24
183.26
189.28 |
6.741
6.978
7.215
7.452 |
171.22
177.24
183.26
189.28 |
6.216
6.453
6.690
6.927 |
157.89
163.91
169.93
175.95 |
32
33
34
35 |
16
16 1/2
17
17 1/2 |
7.689
7.926
8.163
8.401 |
195.30
201.32
207.34
213.39 |
7.689
7.926
8.163
8.401 |
195.30
201.32
207.34
213.39 |
7.164
7.401
7.638
7.876 |
181.97
187.99
194.01
200.05 |
36
37
38
39 |
18
18 1/2
19
19 1/2 |
8.638
8.876
9.113
9.351 |
219.41
225.45
231.47
237.52 |
8.638
8.876
9.113
9.351 |
219.41
225.45
231.47
237.52 |
8.113
8.351
8.588
8.826 |
206.07
212.12
218.14
224.18 |
40
41 |
20
20 1/2 |
9.589
9.826 |
243.56
249.60 |
9.589
9.826 |
243.56
249.60 |
9.064
9.301 |
230.23
236.25 |
