THREAD FINDER | ||||||||||||||||||||
threads per inch | ||||||||||||||||||||
diameter of bolt in inches | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 16 | 18 | 19 | 20 | 22 | 24 | 26 | 28 | 32 | 36 | 40 | ||
1/8 | BSW | |||||||||||||||||||
3/16 | BSW | BSC
BSF ME |
||||||||||||||||||
1/4 | NPS NPT |
BSP | UNC BSW |
BSC BSB BSF CEI |
UNF | UNEF ME |
||||||||||||||
5/16 | ACME | UNC BSW |
BSF | UNF | BSC BSB CEI |
UNEF ME |
||||||||||||||
3/8 | ACME | UNC BSW |
NPS NPT |
BSPP | BSF | UNF | BSC BSB CEI |
UNEF ME |
||||||||||||
7/16 | ACME | UNC BSW |
BSF | UNF | BSC BSB CEI |
UNEF | ME | |||||||||||||
1/2 | ACME | BSW | UNC | NPT NPS BSP |
BSF | UNF | BSC BSB CEI |
UNEF | ME | |||||||||||
9/16 | UNC BSW |
BSF | UNF | BSC | UNEF | BSC BSB CEI |
||||||||||||||
5/8 | UNC BSW |
BSPP BSF |
UNF | UNEF | BSC BSB CEI |
|||||||||||||||
11/16 | BSW | BSF | ||||||||||||||||||
3/4 | UNC BSW |
BSF | NPT NPS |
UNF | UNEF | BSC BSB CEI |
||||||||||||||
13/16 | BSW | BSF | CEI BSB |
UNEF CEI BSB |
CEI BSB |
CEI BSB |
||||||||||||||
7/8 | UNC BSW |
BSF | BSPP UNF |
UNEF | CEI | |||||||||||||||
15/16 | BSW | BSF | UNEF | |||||||||||||||||
1" | UNC BSW |
BSF | UNF | BSPP | UNEF | CEI | ||||||||||||||
8 | 9 | 10 | 11 | 12 | 13 | 14 | 16 | 18 | 19 | 20 | 22 | 24 | 26 | 28 | 32 | 36 | 40 | |||
BSPP | British Standard Pipe Parallel | UNC | Unified National Course | |||||||||||||||||
BSW | British Standard Whitworth | UNF | Unified National Fine | |||||||||||||||||
BSF | British Standard Fine | UNEF | Unified National Extra Fine | |||||||||||||||||
BSB | British Standard Brass | ACME | from the original manufactor Acme Machinery Co. | |||||||||||||||||
BSC | British Standard Cycle | NPS | American National Straight Pipe | |||||||||||||||||
CEI | Cycle Engineers Institute | NPT | American National Pipe Taper | |||||||||||||||||
ME | Model Engineers |
Supplied by DA7C member Peter Marsh with many thanks. CLICK HERE FOR PRINTABLE PDF VERSION
BSP
(British Pipe Thread) can be both parallel and tapered. Properly, but never
seen, they should be named BSPP and BSPT.
Although the thread
form
follows the British Standard Whitworth standard, sizes are not the same diameter
or number of TPI.
The sizes seem a bit small but were originally
based on the inner
diameter (measured in inches) of a steel tube for which the thread was intended,
but contemporary pipes tend to use thinner walls to save material, and thus have
an inner diameter larger than this nominal size.
BSP size |
Thread |
Major |
Minor |
Tapping drill |
|||
P 95% |
T 80% |
||||||
(in)
|
(in−1) |
(mm)
|
(in) |
(mm)
|
(in) |
(mm) |
(mm) |
1⁄16 |
28 |
0.907 |
0.3041 |
7.723 |
0.2583 |
6.6 |
6.8 |
1⁄8 |
28 |
0.907 |
0.3830 |
9.728 |
0.3372 |
8.6 |
8.8 |
1⁄4 |
19 |
1.337 |
0.5180 |
13.157 |
0.4506 |
11.5 |
11.8 |
3⁄8 |
19 |
1.337 |
0.6560 |
16.662 |
0.5886 |
15.0 |
15.3 |
1⁄2 |
14 |
1.814 |
0.8250 |
20.955 |
0.7335 |
18.7 |
19.1 |
5⁄8 |
14 |
1.814 |
0.9020 |
22.911 |
0.8105 |
20.7 |
21.1 |
3⁄4 |
14 |
1.814 |
1.0410 |
26.441 |
0.9495 |
24.2 |
24.6 |
7⁄8 |
14 |
1.814 |
1.1890 |
30.201 |
1.0975 |
28.0 |
28.3 |
1 |
11 |
2.309 |
1.3090 |
33.249 |
1.1926 |
30.4 |
30.9 |