MARYLAND METRICS
THREAD DATA CHARTS
NATIONAL PIPE TAPERED THREAD (NPT)
NPT Thread - American Standard Taper Pipe Thread ANSI B 1.20.1, Taper 1:16
Thread Form Data
* Ream the hole before tapping with a reamer having a taper of 3/4 inch per foot.
Pipe Size is the accepted industry designation and
does not refer to either the inside or the outside diameter (ID or OD) of a pipe or a fitting.
Dimensions in Inches except where stated
Click here to return to the thread data chart page index.
Phones: (800) 638-1830 or (410) 358-3130 are available Monday-Friday 8:30 AM to 5:30 PM Eastern time.
Faxes: (800) 872-9329 or (410) 358-3142 & E-mail are available anytime.
Warehouse & showroom hours are Monday-Friday 10 AM to 5:30 PM.
[ To: Maryland Metrics home page ] [ To: Maryland Metrics Product Guide ] [ e-mail to Maryland Metrics ]
Please note that all Trademarks and Tradenames are the property of their respective owners.
copyright 2008 maryland metrics -- all rights reserved -- ver dd09fCD thddat19.htm
Thread Form Data
| Pipe | Tapping Drills | |||||||||
| NPT Size (in) | Threads per Inch |
Pitch (mm) | Nom. OD (in) |
Nom. OD (mm) |
Taper NPT with Reamer * | Taper NPT without Reamer | ||||
| Drill Size | Equivalents | Drill Size | Equivalents | |||||||
| (in) | (mm) | (in) | (mm) | |||||||
| 1/16 | 27 | 0.941 | 0.313 | 7.938 | 15/64" | 0.2344 | 5.9531 | C | 0.2420 | 6.1468 |
| 1/8 | 27 | 0.941 | 0.405 | 10.287 | 21/64" | 0.3281 | 8.3344 | Q | 0.3320 | 8.4328 |
| 1/4 | 18 | 1.411 | 0.540 | 13.716 | 27/64" | 0.4219 | 10.7156 | 7/16" | 0.4375 | 11.1125 |
| 3/8 | 18 | 1.411 | 0.675 | 17.145 | 9/16" | 0.5625 | 14.2875 | 37/64" | 0.5781 | 14.6844 |
| 1/2 | 14 | 1.814 | 0.840 | 21.336 | 11/16" | 0.6875 | 17.4625 | 45/64" | 0.7031 | 17.8594 |
| 3/4 | 14 | 1.814 | 1.050 | 26.670 | 57/64" | 0.8906 | 22.6219 | 29/32" | 0.9063 | 23.0188 |
| 1 | 11-1/2 | 2.209 | 1.315 | 33.401 | 1-1/8" | 1.1250 | 28.5750 | 1-9/32" | 1.2813 | 32.5438 |
| 1-1/4 | 11-1/2 | 2.209 | 1.660 | 42.164 | 1-15/32" | 1.4688 | 37.3063 | 1-31/64" | 1.4844 | 37.7031 |
| 1-1/2 | 11-1/2 | 2.209 | 1.900 | 48.260 | 1-23/32" | 1.7188 | 43.6563 | 1-23/32" | 1.7188 | 43.6563 |
| 2 | 11-1/2 | 2.209 | 2.375 | 60.325 | 2-5/32" | 2.1563 | 54.7688 | 2-3/16" | 2.1875 | 55.5625 |
| 2-1/2 | 8 | 3.175 | 2.875 | 73.025 | 2-25/32" | 2.7813 | 70.6438 | 2-5/8" | 2.6250 | 66.6750 |
| 3 | 8 | 3.175 | 3.500 | 88.900 | 3-9/32" | 3.2813 | 83.3438 | 3-1/4" | 3.2500 | 82.5500 |
| 3-1/2 | 8 | 3.175 | 4.000 | 101.600 | 3-3/4" | 3.7500 | 95.2500 | 3-3/4" | 3.7500 | 95.2500 |
| 4 | 8 | 3.175 | 4.500 | 114.300 | 4-1/4" | 4.2500 | 107.9500 | 4-1/4" | 4.2500 | 107.9500 |
| 5 | 8 | 3.175 | 5.563 | 141.300 | 5-1/4" | 5.2500 | 133.3500 | 5-9/32" | 5.2813 | 134.1438 |
| 6 | 8 | 3.175 | 6.625 | 168.275 | 6-1/4" | 6.2500 | 158.7500 | 6-11/32" | 6.3438 | 161.1313 |
Pipe Size is the accepted industry designation and
does not refer to either the inside or the outside diameter (ID or OD) of a pipe or a fitting.
Dimensions in Inches except where stated
Click here to return to the thread data chart page index.
Phones: (800) 638-1830 or (410) 358-3130 are available Monday-Friday 8:30 AM to 5:30 PM Eastern time.
Faxes: (800) 872-9329 or (410) 358-3142 & E-mail are available anytime.
Warehouse & showroom hours are Monday-Friday 10 AM to 5:30 PM.
[ To: Maryland Metrics home page ] [ To: Maryland Metrics Product Guide ] [ e-mail to Maryland Metrics ]
Please note that all Trademarks and Tradenames are the property of their respective owners.
copyright 2008 maryland metrics -- all rights reserved -- ver dd09fCD thddat19.htm