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THREAD DIMENSION CHARTSNational Pipe Taper

NPT3⁄8"1⁄2"3⁄4"1"

11⁄4"11⁄2"2"

21⁄2"3"

31⁄2"4"

Major Dia.17.05mm21.22mm26.57mm33.23mm41.99mm48.05mm60.09mm72.70mm88.61mm101.60mm114.30mm

TPI181414

11.511.511.511.5

8888

PG DIN 40430PG

PG7PG9PG11

PG13.5PG16PG21PG29PG36PG42PG48

Major Dia.12.50mm15.20mm18.60mm20.40mm22.50mm28.30mm37.00mm47.00mm54.00mm59.30mm

TPI20181818181616161616

BSP BS2779BSP

3⁄8"1⁄2"3⁄4"1"

11⁄4"11⁄2"2"

21⁄2"3"

Major Dia.16.66mm20.96mm26.44mm33.25mm41.91mm47.80mm59.61mm75.18mm87.88mm

TPI191414111111111111

Imperial Conduit BS31ET5⁄8"3⁄4"1"

11⁄4"11⁄2"2"

21⁄2"3"

Major Dia.15.88mm19.05mm25.40mm31.75mm38.10mm50.80mm63.50mm76.20mm

TPI1816161614141414

THREAD FORM COMPARISON CHART

Note 1: PF Thread Form (Japan) = BSP ParallelG Thread Form (Europe) = BSP ParallelGK Thread Form (Europe) = BSP Taper

Note 2: NPT/BSPT Taper @ 1⁄16 on Major Dia.

ISO Metric – 1.5mm PitchMetricM16M20M25M32M40M50M63M75M90M100

Major Dia.15.97mm19.97mm24.97mm31.97mm39.97mm49.97mm62.97mm74.97mm89.97mm99.97mm

TPI16.9316.9316.9316.9316.9316.9316.9316.9312.7012.70

MetricM16M20M25M32M40M50M63M75M90M100

NPT3⁄8"1⁄2"3⁄4"1"

11⁄4"11⁄2"2"

21⁄2"3"

31⁄2"

PG7, 9, 1113.5, 16PG21PG29PG36PG42PG48

BSP3⁄8"1⁄2"3⁄4"1"

11⁄4"11⁄2"2"

21⁄2"3"

ET5⁄8"3⁄4"1"

11⁄4"11⁄2"2"

21⁄2"3"

Thread Conversion Specialists