1-11.5 NPSH NPSH (pipe-size hose) External Thread Specifications

1-11.5NPSH EXT

ASMESTD: ASME B1.20.7SOURCE: Table 2 · p. 5TYPE: External (bolt/screw)CLASS: StdSERIES: NPSH (pipe-size hose)
Major diameter
1.2951 – 1.2781
max – min
Pitch diameter
1.2386 – 1.2301
max – min
Minor diameter
1.1821 – 1.1611
max – min
Pitch
0.08696
11.5 threads per inch

Thread profile

1-11.5NPSH EXT: external M profile with its tolerance zone, drawn to scaled = 1.305d2 = 1.249d1 = 1.192P = 0.0869660°30°crest 0.010870root 0.010870Major dia zone (crest)1.295 – 1.278 Td 0.017Pitch dia zone (flanks)1.239 – 1.230 Td2 0.009Root zone (minor dia)1.182 – 1.161Fundamental deviationes = −0.010 (allowance)H/80.0094143H/80.028241H/40.018827h = 5H/80.056480H0.075307thread axis, 0.653 in below the major radius (diameters shortened)MALE · external thread · 1-11.5NPSH EXT

1-11.5NPSH 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 tolerance1.30511.29511.27810.0170
Pitch diameter d21.24861.23861.23010.0085
Minor diameter d1Max printed; min is a reference value1.19211.18211.1611ref.0.0211ref.
Allowance es0.0100

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 −0.010ei −0.018male pitch dia Stdes −0.010des −0.010ei −0.027male major dia (crest)es −0.010

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-1
Mating member of the same designation
1-11.5NPSH INT
Other designations in the mating group
none (mates only with its own designation)
Minimum PD clearance (coupling min − nipple max)
0.0100 in
Maximum PD clearance (coupling max − nipple min)
0.0270 in
Minimum major dia clearance
0.0100 in
Minimum minor dia clearance
0.0100 in
Fit at the limits (PD)
clearance (always)

Lead, flank and profile

Lead variation ± (Table 5) ±δP
0.0025 in
Half-angle variation ± (Table 5) ±δα
1° 52′
Lead angle at the basic PD λ
1° 16′
Crest flat (basic P/8)
0.010870 in
Root flat (basic P/8)
0.010870 in
Extreme flat P/24 at minimum PD
0.003623 in
Root radius for the model (worn tool) r
0.009413 in

Table 4 dimensions (nipple and coupling)

As printed
C 1 1/32; OD 1 9/32; L 9/16; l 5/32
Inside diameter of the nipple C
1.03125 in
Approximate OD of the external thread OD
1.28125 in
Length of the nipple L
0.56250 in
Pilot length l
0.15625 in

Ring gages (Table 6)

GO pitch max / min
1.2386 / 1.2383 in
GO minor max / min
1.1921 / 1.1915 in
NOT GO pitch max / min
1.2304 / 1.2301 in
NOT GO minor max / min
1.2119 / 1.2113 in
Z GO major max / min
1.29510 / 1.29498 in
Z NOT GO major max / min
1.27822 / 1.27810 in

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

GO truncated major max / min
1.2818 / 1.2812 in
GO full major max / min
1.2957 / 1.2951 in
GO pitch max / min
1.2386 / 1.2383 in
NOT GO truncated major max / min
1.2678 / 1.2672 in
NOT GO pitch max / min
1.2304 / 1.2301 in

Notes

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

Mates

1-11.5NPSH 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

→ 1-8 NH-FIRE→ 3/4-14 NPSH→ 1 1/4-11.5 NPSH→ 1-11.5 NPSH internal
All values for 1-11.5NPSH EXTevery column of the workbook row
All values of the workbook row 1-11.5NPSH EXT
Designation1-11.5NPSH EXT
Decimal / alternate designation1.0000-11.5NPSH EXT
Threads per inch11.5
Thread formNPSH
SeriesNPSH
Series nameHose to pipe thread (NPSH)
External / internalExternal
ClassStd
Nominal size of hose1
Pitch P (in.)0.08696
Basic major dia D (in.)1.3051
Size categoryStandard sizes (Tables 1-8)
Source tableTable 2
Printed page5
Major dia max (in.)1.2951
Major dia min (in.)1.2781
Major dia tolerance (in.)0.0170
Allowance es (in.)0.0100
Basic pitch dia D2 (in.)1.2486
Pitch dia max (in.)1.2386
Pitch dia min (in.)1.2301
PD tolerance (in.)0.0085
Basic minor dia D1 (in.)1.1921
Minor dia max (in.)1.1821
Minor dia min (in.)1.1611
Minor dia tolerance (in.)0.0211
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)0.0025
Half-angle variation ± (Table 5)1° 52′
Lead variation from PD tol (calc) (in.)0.0025
Half-angle variation from PD tol (calc)1° 52′
Lead angle at basic PD (deg)1.2699
Lead angle (deg min)1° 16′
Tensile stress area As (sq in.)not given in the standard
Thread angle (deg)60
Flank angle (deg)30
Sharp V height H (in.)0.075307
Thread height h (in.)0.056480
Crest flat, basic P/8 (in.)0.010870
Root flat, basic P/8 (in.)0.010870
Extreme flat P/24 at minimum PD (in.)0.003623
Truncation of the P/8 flat from the sharp V, f = h/6 (in.)0.009413
Root radius for model (worn tool) (in.)0.009413
Sweep cut: start diameter (in.)1.295100
Sweep cut: tip diameter (in.)1.182100
Sweep cut: depth (in.)0.056500
Sweep cut: profile width at start diameter (in.)0.076110
Crest flat as modelled (in.)0.010847
Tapernone (straight thread)
ServiceSteam, air, water, and all other hose connections to be made up with standard pipe threads
Mating group (compatible designations)NPSH-1
Mating member of the same designation1-11.5NPSH INT
Other designations in the mating groupnone (mates only with its own designation)
Min PD clearance: coupling min PD - nipple max PD (in.)0.0100
Max PD clearance: coupling max PD - nipple min PD (in.)0.0270
Min major dia clearance: coupling min - nipple max (in.)0.0100
Min minor dia clearance: coupling min - nipple max (in.)0.0100
Fit at the limits (PD)clearance (always)
Table 4 lengths as printedC 1 1/32; OD 1 9/32; L 9/16; l 5/32
Table 4: C inside dia of nipple (in.)1.03125
Table 4: approx OD of external thread (in.)1.28125
Table 4: L length of nipple (in.)0.56250
Table 4: l pilot length (in.)0.15625
Table 6 ring gage: GO pitch max (in.)1.2386
Table 6 ring gage: GO pitch min (in.)1.2383
Table 6 ring gage: GO minor max (in.)1.1921
Table 6 ring gage: GO minor min (in.)1.1915
Table 6 ring gage: NOT GO pitch max (in.)1.2304
Table 6 ring gage: NOT GO pitch min (in.)1.2301
Table 6 ring gage: NOT GO minor max (in.)1.2119
Table 6 ring gage: NOT GO minor min (in.)1.2113
Table 6 ring gage: Z GO major max (in.)1.29510
Table 6 ring gage: Z GO major min (in.)1.29498
Table 6 ring gage: Z NOT GO major max (in.)1.27822
Table 6 ring gage: Z NOT GO major min (in.)1.27810
Table 8 setting plug: GO truncated major max (in.)1.2818
Table 8 setting plug: GO truncated major min (in.)1.2812
Table 8 setting plug: GO full major max (in.)1.2957
Table 8 setting plug: GO full major min (in.)1.2951
Table 8 setting plug: GO pitch max (in.)1.2386
Table 8 setting plug: GO pitch min (in.)1.2383
Table 8 setting plug: NOT GO truncated major max (in.)1.2678
Table 8 setting plug: NOT GO truncated major min (in.)1.2672
Table 8 setting plug: NOT GO full major max (in.)1.2957
Table 8 setting plug: NOT GO full major min (in.)1.2951
Table 8 setting plug: NOT GO pitch max (in.)1.2304
Table 8 setting plug: NOT GO pitch min (in.)1.2301
Table 8 setting plug: Full-form GO major max (in.)1.2957
Table 8 setting plug: Full-form GO major min (in.)1.2951
Table 8 setting plug: Full-form NOT GO major max (in.)1.2957
Table 8 setting plug: Full-form NOT GO major min (in.)1.2951
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.