Taper Pipe Tap Thread Limits
| NOMINAL SIZE INCHES |
THREADS PER INCH |
STANDARD PROJECTION NPT & NPTF |
PTF SAE SHORT PROJECTION |
| PROJECTION THROUGH L1 RING GAGE |
THICKNESS OF L1 RING GAGE |
RUN OF THREAD |
PROJECTION THROUGH L1 RING GAGE |
THICKNESS OF L1 RING GAGE |
RUN OF THREAD |
| 1/16 |
27 |
0.312 |
0.16 |
0.472 |
.2405.019 |
0.16 |
0.4005 |
| 1/8 |
27 |
0.312 |
0.1615 |
0.4735 |
.2405.019 |
0.1615 |
0.402 |
| 1/4 |
18 |
0.459 |
0.2278 |
0.6868 |
.3610.028 |
0.2278 |
0.5888 |
| 3/8 |
18 |
0.454 |
0.24 |
0.694 |
.3610.028 |
0.24 |
0.601 |
| 1/2 |
14 |
0.579 |
0.32 |
0.899 |
.4645.036 |
0.32 |
0.7845 |
| 3/4 |
14 |
0.565 |
0.339 |
0.904 |
.4645.036 |
0.339 |
0.8035 |
| 1 |
11 1/2 |
0.678 |
0.4 |
1.078 |
.5652.044 |
0.4 |
0.9652 |
| 1 1/4 |
11 1/2 |
0.686 |
0.42 |
1.106 |
.5652.044 |
0.42 |
0.9852 |
| 1 1/2 |
11 1/2 |
0.699 |
0.42 |
1.119 |
.5652.044 |
0.42 |
0.9852 |
| 2 |
11 1/2 |
0.667 |
0.436 |
1.103 |
.5652.044 |
0.436 |
1.0012 |
| 2 1/2 |
8 |
0.925 |
0.682 |
1.607 |
.8125.062 |
0.682 |
1.4945 |
| 3 |
8 |
0.925 |
0.766 |
1.691 |
.8125.062 |
0.766 |
1.5785 |
| 3 1/2 |
8 |
0.938 |
0.821 |
1.759 |
|
|
|
| 4 |
8 |
0.95 |
0.844 |
1.794 |
|
|
|
Projection & Thickness L1 Ring Gage = Run
Gage Measurement in inches