r = Basic Radius = 0.137278 p
h = Basic Depth of Thread = 0.640327 p
p = Pitch = 1/t.p.i.
Taper is 1 in 16 on Diameter ( Exaggerated in Drawing)
Angle of Thread = 55o Degrees
Not one I've seen, or at least recognised. This may be the thread for sump plugs etc, but as these are always oily, I've never had problems with one of these.
r = Basic Radius = 0.137278 p
h = Basic Depth of Thread = 0.640327 p
p = Pitch = 1/t.p.i.
Taper is 1 in 16 on Diameter ( Exaggerated in Drawing)
Angle of Thread = 55o Degrees
| 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 | 6.4 mm (0.2520 inch) |
| 1/8 | 28 | 0.0357 | 0.383 | 0.3372 | 8.4 mm (0.3307 inch) |
| 1/4 | 19 | 0.0526 | 0.518 | 0.4506 | 11.2 mm (0.4409 inch) |
| 3/8 | 19 | 0.0526 | 0.656 | 0.5886 | 14.75 mm (0.0507 inch) |
| 1/ 2 | 14 | 0.0714 | 0.825 | 0.7336 | 18.25 mm (0.7185 inch) |
| 3/4 | 14 | 0.0714 | 1.041 | 0.9496 | 23.75 mm (0.9350 inch) |
| 1 inch | 11 | 0.0909 | 1.309 | 1.1926 | 30 mm (1.1811 inch) |
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