3/4-14 NPSH NPSH (pipe-size hose) External Thread Specifications

3/4-14NPSH EXT

ASMESTD: ASME B1.20.7SOURCE: Table 2 · p. 5TYPE: External (bolt/screw)CLASS: StdSERIES: NPSH (pipe-size hose)
Major diameter
1.0353 – 1.0213
max – min
Pitch diameter
0.9889 – 0.9819
max – min
Minor diameter
0.9425 – 0.9252
max – min
Pitch
0.07143
14 threads per inch

Thread profile

3/4-14NPSH EXT: external M profile with its tolerance zone, drawn to scaled = 1.043d2 = 0.996d1 = 0.950P = 0.0714360°30°crest 0.008929root 0.008929Major dia zone (crest)1.035 – 1.021 Td 0.014Pitch dia zone (flanks)0.989 – 0.982 Td2 0.007Root zone (minor dia)0.943 – 0.925Fundamental deviationes = −0.007 (allowance)H/80.0077333H/80.023198H/40.015465h = 5H/80.046394H0.061859thread axis, 0.521 in below the major radius (diameters shortened)MALE · external thread · 3/4-14NPSH EXT

3/4-14NPSH EXT: solid line = maximum material profile, dashed = minimum material, hatched = tolerance zone, grey dashed = basic profile. Drawn to scale; values in inches, diameters shortened.

Limits of size, class Std

DimensionBasicMaxMinTolerance
Major diameter dPara. 3.1: tolerance = 2 × PD tolerance1.04281.03531.02130.0140
Pitch diameter d20.99640.98890.98190.0070
Minor diameter d1Max printed; min is a reference value0.95000.94250.9252ref.0.0173ref.
Allowance es0.0075

Dimensions in inches. Values are those of the standard (ASME B1.20.7); calculated cells follow the standard’s formulas. Where the standard prints a value that differs from its formula, the printed value is shown with a note.

Tolerance zones relative to the basic size, inches

Tolerance zones relative to the basic sizezero line = basic size+ above · − belowd2es −0.007ei −0.014male pitch dia Stdes −0.007des −0.007ei −0.021male major dia (crest)es −0.007

Mating, gaging and dimensions

Mating member and fit at the limits

Service
Steam, air, water, and all other hose connections to be made up with standard pipe threads
Mating group (compatible designations)
NPSH-3/4
Mating member of the same designation
3/4-14NPSH INT
Other designations in the mating group
none (mates only with its own designation)
Minimum PD clearance (coupling min − nipple max)
0.0075 in
Maximum PD clearance (coupling max − nipple min)
0.0215 in
Minimum major dia clearance
0.0075 in
Minimum minor dia clearance
0.0075 in
Fit at the limits (PD)
clearance (always)

Lead, flank and profile

Lead variation ± (Table 5) ±δP
0.0020 in
Half-angle variation ± (Table 5) ±δα
1° 52′
Lead angle at the basic PD λ
1° 18′
Crest flat (basic P/8)
0.008929 in
Root flat (basic P/8)
0.008929 in
Extreme flat P/24 at minimum PD
0.002976 in
Root radius for the model (worn tool) r
0.007732 in

Table 4 dimensions (nipple and coupling)

As printed
C 25/32; OD 1 1/32; L 9/16; l 1/8
Inside diameter of the nipple C
0.78125 in
Approximate OD of the external thread OD
1.03125 in
Length of the nipple L
0.56250 in
Pilot length l
0.12500 in

Ring gages (Table 6)

GO pitch max / min
0.9889 / 0.9886 in
GO minor max / min
0.9500 / 0.9494 in
NOT GO pitch max / min
0.9822 / 0.9819 in
NOT GO minor max / min
0.9670 / 0.9664 in
Z GO major max / min
1.03530 / 1.03518 in
Z NOT GO major max / min
1.02142 / 1.02130 in

Setting plugs (Table 8) and plug gages (Table 7)

GO truncated major max / min
1.0238 / 1.0232 in
GO full major max / min
1.0359 / 1.0353 in
GO pitch max / min
0.9889 / 0.9886 in
NOT GO truncated major max / min
1.0128 / 1.0122 in
NOT GO pitch max / min
0.9822 / 0.9819 in

Notes

  • Root radius and tensile stress area are not given in the standard.

Mates

3/4-14NPSH EXT screws into a thread of the same standard at the same size and pitch. The standard mating internal thread is class Std. Check the fit with the standard pair →

Working out the mating options…

Different pitch or a different thread family never mate; the fit check runs over both tolerance zones.

Related thread sizes

Same diameter other pitch, and neighbouring sizes

→ 3/4-11.5 NH→ 3/4-11.5 NHR→ 1/2-14 NPSH→ 1-11.5 NPSH→ 3/4-14 NPSH internal
All values for 3/4-14NPSH EXTevery column of the workbook row
All values of the workbook row 3/4-14NPSH EXT
Designation3/4-14NPSH EXT
Decimal / alternate designation0.7500-14NPSH EXT
Threads per inch14
Thread formNPSH
SeriesNPSH
Series nameHose to pipe thread (NPSH)
External / internalExternal
ClassStd
Nominal size of hose3/4
Pitch P (in.)0.07143
Basic major dia D (in.)1.0428
Size categoryStandard sizes (Tables 1-8)
Source tableTable 2
Printed page5
Major dia max (in.)1.0353
Major dia min (in.)1.0213
Major dia tolerance (in.)0.0140
Allowance es (in.)0.0075
Basic pitch dia D2 (in.)0.9964
Pitch dia max (in.)0.9889
Pitch dia min (in.)0.9819
PD tolerance (in.)0.0070
Basic minor dia D1 (in.)0.9500
Minor dia max (in.)0.9425
Minor dia min (in.)0.9252
Minor dia tolerance (in.)0.0173
Major dia statusToleranced (para. 3.1: tolerance = 2 x PD tolerance)
Minor dia statusMaximum printed; minimum is a reference value (para. 3.1: P/24 flat at min PD)
Root radius max (in.)not given in the standard
Root radius min (in.)not given in the standard
Lead variation ± (in.) (Table 5)0.0020
Half-angle variation ± (Table 5)1° 52′
Lead variation from PD tol (calc) (in.)0.0020
Half-angle variation from PD tol (calc)1° 52′
Lead angle at basic PD (deg)1.3072
Lead angle (deg min)1° 18′
Tensile stress area As (sq in.)not given in the standard
Thread angle (deg)60
Flank angle (deg)30
Sharp V height H (in.)0.061859
Thread height h (in.)0.046394
Crest flat, basic P/8 (in.)0.008929
Root flat, basic P/8 (in.)0.008929
Extreme flat P/24 at minimum PD (in.)0.002976
Truncation of the P/8 flat from the sharp V, f = h/6 (in.)0.007732
Root radius for model (worn tool) (in.)0.007732
Sweep cut: start diameter (in.)1.035300
Sweep cut: tip diameter (in.)0.942500
Sweep cut: depth (in.)0.046400
Sweep cut: profile width at start diameter (in.)0.062507
Crest flat as modelled (in.)0.008922
Tapernone (straight thread)
ServiceSteam, air, water, and all other hose connections to be made up with standard pipe threads
Mating group (compatible designations)NPSH-3/4
Mating member of the same designation3/4-14NPSH INT
Other designations in the mating groupnone (mates only with its own designation)
Min PD clearance: coupling min PD - nipple max PD (in.)0.0075
Max PD clearance: coupling max PD - nipple min PD (in.)0.0215
Min major dia clearance: coupling min - nipple max (in.)0.0075
Min minor dia clearance: coupling min - nipple max (in.)0.0075
Fit at the limits (PD)clearance (always)
Table 4 lengths as printedC 25/32; OD 1 1/32; L 9/16; l 1/8
Table 4: C inside dia of nipple (in.)0.78125
Table 4: approx OD of external thread (in.)1.03125
Table 4: L length of nipple (in.)0.56250
Table 4: l pilot length (in.)0.12500
Table 6 ring gage: GO pitch max (in.)0.9889
Table 6 ring gage: GO pitch min (in.)0.9886
Table 6 ring gage: GO minor max (in.)0.9500
Table 6 ring gage: GO minor min (in.)0.9494
Table 6 ring gage: NOT GO pitch max (in.)0.9822
Table 6 ring gage: NOT GO pitch min (in.)0.9819
Table 6 ring gage: NOT GO minor max (in.)0.9670
Table 6 ring gage: NOT GO minor min (in.)0.9664
Table 6 ring gage: Z GO major max (in.)1.03530
Table 6 ring gage: Z GO major min (in.)1.03518
Table 6 ring gage: Z NOT GO major max (in.)1.02142
Table 6 ring gage: Z NOT GO major min (in.)1.02130
Table 8 setting plug: GO truncated major max (in.)1.0238
Table 8 setting plug: GO truncated major min (in.)1.0232
Table 8 setting plug: GO full major max (in.)1.0359
Table 8 setting plug: GO full major min (in.)1.0353
Table 8 setting plug: GO pitch max (in.)0.9889
Table 8 setting plug: GO pitch min (in.)0.9886
Table 8 setting plug: NOT GO truncated major max (in.)1.0128
Table 8 setting plug: NOT GO truncated major min (in.)1.0122
Table 8 setting plug: NOT GO full major max (in.)1.0359
Table 8 setting plug: NOT GO full major min (in.)1.0353
Table 8 setting plug: NOT GO pitch max (in.)0.9822
Table 8 setting plug: NOT GO pitch min (in.)0.9819
Table 8 setting plug: Full-form GO major max (in.)1.0359
Table 8 setting plug: Full-form GO major min (in.)1.0353
Table 8 setting plug: Full-form NOT GO major max (in.)1.0359
Table 8 setting plug: Full-form NOT GO major min (in.)1.0353
Check against formulasOK
NotesRoot radius and tensile stress area are not given in the standard.

Related tools

ASME B1.20.7: Hose Coupling Screw Threads, Inch. Source: workbook data (2026-10-10). Confirm against your licensed copy of the standard before use.