Buttress Inch Threads Chart
| BASIC DIMENSIONS AND PITCH | ||||
|---|---|---|---|---|
| TPI | Pitch P (in) | Basic height 0.6P (in) | Thread height 0.66271P (in) | Root radius 0.07141P (in) |
| 20 | .0500 | .0300 | .0331 | .0036 |
| 16 | .0625 | .0375 | .0414 | .0045 |
| 12 | .0833 | .0500 | .0552 | .0059 |
| 10 | .1000 | .0600 | .0663 | .0071 |
| 8 | .1250 | .0750 | .0828 | .0089 |
| 6 | .1667 | .1000 | .1105 | .0119 |
| 5 | .2000 | .1200 | .1325 | .0143 |
| 4 | .2500 | .1500 | .1657 | .0179 |
| 3 | .3333 | .2000 | .2209 | .0238 |
| 2 1/2 | .4000 | .2400 | .2651 | .0286 |
| 2 | .5000 | .3000 | .3314 | .0357 |
| 1 1/2 | .6667 | .4000 | .4418 | .0476 |
| 1 1/4 | .8000 | .4800 | .5302 | .0572 |
| 1 | 1.0000 | .6000 | .6627 | .0714 |
Buttress threads are often designed for a particular component, so diameter/pitch combinations are selected for the application. This table gives the standard 7°/45° basic profile dimensions by pitch.