| The reference number for the diameter of a glass tube is given by taking the largest diameter measured in inches divided by 1/8 inch (0.125"). Due to tolerances, the manufacturers' numbers may not always match the theoretical ones. |
G: |
Globel look |
MT: |
Metal tube Tubular look |
MTT: |
Metal tube with with Two different Tubular dimensions |
S: |
Straight side |
ST: |
combination of S and T (dome type) |
T: |
Tubular look |
Inch nom |
Inch min |
Inch max |
mm min |
mm max |
|
| T-1 | 0,125 |
0,220 |
5,5 |
||
| T-1.5 | 0,188 |
0,205 |
0,267 |
5,0 |
6,8 |
| T-2 | 0,250 |
0,267 |
0,315 |
6,8 |
8,0 |
| T-3 | 0,375 |
0,315 |
0,438 |
8,0 |
11,1 |
| T-4 | 0,500 |
0,438 |
0,531 |
11,1 |
13,5 |
| T-4.5 | 0,563 |
0,531 |
0,594 |
13,5 |
15,1 |
| T-5 | 0,625 |
0,594 |
0,656 |
15,1 |
16,7 |
| T-5.5 | 0,688 |
0,656 |
0,719 |
16,7 |
18,3 |
| T-6 | 0,750 |
0,719 |
0,781 |
18,3 |
19,8 |
| T-6.5 | 0,813 |
0,781 |
0,844 |
19,8 |
21,4 |
| T-7 | 0,875 |
0,844 |
0,906 |
21,4 |
23,0 |
| T-7.5 | 0,938 |
0,906 |
0,969 |
23,0 |
24,6 |
| T-8 | 1,000 |
0,969 |
1,063 |
24,6 |
27,0 |
| T-9 | 1,125 |
1,063 |
1,188 |
27,0 |
30,2 |
| T-10 | 1,250 |
1,188 |
1,313 |
30,2 |
33,3 |
| T-11 | 1,375 |
1,313 |
1,438 |
33,3 |
36,5 |
| T-12 | 1,500 |
1,438 |
1,563 |
36,5 |
39,7 |
| T-13 | 1,625 |
1,563 |
1,688 |
39,7 |
42,9 |
| T-14 | 1,750 |
1,688 |
1,813 |
42,9 |
46,0 |
| T-15 | 1,875 |
1,813 |
1,938 |
46,0 |
49,2 |
| T-16 | 2,000 |
1,938 |
2,063 |
49,2 |
52,4 |
| T-17 | 2,125 |
2,063 |
2,188 |
52,4 |
55,6 |
| T-18 | 2,250 |
2,188 |
2,313 |
55,6 |
58,7 |
| T-19 | 2,375 |
2,313 |
2,438 |
58,7 |
61,9 |
| T-20 | 2,500 |
2,438 |
2,563 |
61,9 |
65,1 |
| T-21 | 2,625 |
2,563 |
2,688 |
65,1 |
68,3 |
| T-22 | 2,750 |
2,688 |
2,813 |
68,3 |
71,4 |
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"Guide for the determination of Radio Tube Bases"