|
BA |
BSC |
BSF |
BSP |
BSTP |
BSW |
CEI |
UNC |
UNF |
ME |
BSB
BST - British Standard Pipe Threads
Nominal
Size
(inches) |
T
P I |
Pitch
(inches) |
Major
Diameter
(inches) |
Minor
Diameter
(inches) |
Tapping
Drill Size |
| 1/16 |
28 |
0.0357 |
0.304 |
0.2583 |
Letter
drill G
(6.6 mm) |
| 1/8 |
28 |
0.0357 |
0.383 |
0.3372 |
11/32
inch
(8.73 mm) |
| 1/4 |
19 |
0.0526 |
0.518 |
0.4546 |
11.8
mm
(0.4646 inch) |
| 3/8 |
19 |
0.0526 |
0.656 |
0.5886 |
15.25
mm
(0.6004 inch) |
| 1/2 |
14 |
0.0714 |
0.825 |
0.7336 |
3/4
inch
(19.05 mm) |
| 5/8 |
14 |
0.0714 |
0.902 |
0.8106 |
21
mm
(0.8268 inch) |
| 3/4 |
14 |
0.0714 |
1.041 |
0.9496 |
24.5
mm
(0.9646 inch) |
| 7/8 |
14 |
0.0714 |
1.189 |
1.0976 |
28.25
mm
(1.1122 inch) |
| 1
inch |
11 |
0.0909 |
1.309 |
1.1926 |
30.75
mm
(1.2106 inch) |
|
Parallel ('straight') threads, British Standard Pipe Parallel thread (BSPP; originally also known as British Standard Pipe Fitting thread/BSPF and British Standard Pipe Mechanical thread/BSPM), which have a constant diameter.
These can be combined into two types of joints:
Jointing threads: These are pipe threads where pressure-tightness is made through the mating of two threads together. They always use a taper male thread, but can have either parallel or taper female threads. (In Europe, taper female pipe threads are not commonly used.)
Longscrew threads: These are parallel pipe threads used where a pressure-tight joint is achieved by the compression of a soft material (such as an o-ring seal or a washer) between the end face of the male thread and a socket or nipple face, with the tightening of a backnut.
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