2-11.5 NPSH NPSH (pipe-size hose) Internal Thread Specifications

2-11.5NPSH INT

ASMESTD: ASME B1.20.7SOURCE: Table 3 · p. 6TYPE: Internal (nut/tapped hole)CLASS: StdSERIES: NPSH (pipe-size hose)
Major diameter
2.3838 – 2.3628
max – min
Pitch diameter
2.3148 – 2.3063
max – min
Minor diameter
2.2668 – 2.2498
max – min
Pitch
0.08696
11.5 threads per inch

Thread profile

2-11.5NPSH INT: internal M profile with its tolerance zone, drawn to scaleD = 2.363D2 = 2.306D1 = 2.250P = 0.0869660°30°crest 0.010870root 0.010870Major dia (root)2.363 min (2.384 max ref.)Pitch dia zone (flanks)2.306 – 2.315 TD2 0.009Minor dia zone (crests)2.250 – 2.267 TD1 0.017Fundamental deviationEI = 0, position HH/80.0094143H/80.028241H/40.018827h = 5H/80.056480H0.075307thread axis, 1.181 in below the major radius (diameters shortened)FEMALE · internal thread · 2-11.5NPSH INT

2-11.5NPSH INT: 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 tolerance2.36282.3838ref.2.36280.0211ref.
Pitch diameter D22.30632.31482.30630.0085
Minor diameter D12.24982.26682.24980.0170
Allowance es—

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 +0.009EI 0.000female pitch diaD1ES +0.017EI 0.000female minor dia (crest)

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-2
Mating member of the same designation
2-11.5NPSH EXT
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
0° 41′
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
H 23/32; T 19/32; n 6 3/4
Depth of the coupling H
0.71875 in
Thread length of the coupling T
0.59375 in

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

Plug gage GO major max / min
2.3634 / 2.3628 in
Plug gage GO pitch max / min
2.3067 / 2.3063 in
Plug gage NOT GO pitch max / min
2.3148 / 2.3144 in

Notes

  • Maximum major diameter, major diameter tolerance (internal) are reference values from para. 3.2; root radius and stress area are not given in the standard.

Mates

2-11.5NPSH INT takes a thread of the same standard at the same size and pitch. The standard mating external 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 1/2-11.5 NPSH→ 2 1/2-8 NPSH→ 2-11.5 NPSH external
All values for 2-11.5NPSH INTevery column of the workbook row
All values of the workbook row 2-11.5NPSH INT
Designation2-11.5NPSH INT
Decimal / alternate designation2.0000-11.5NPSH INT
Threads per inch11.5
Thread formNPSH
SeriesNPSH
Series nameHose to pipe thread (NPSH)
External / internalInternal
ClassStd
Nominal size of hose2
Pitch P (in.)0.08696
Basic major dia D (in.)2.3628
Size categoryStandard sizes (Tables 1-8)
Source tableTable 3
Printed page6
Major dia max (in.)2.3838
Major dia min (in.)2.3628
Major dia tolerance (in.)0.0211
Basic pitch dia D2 (in.)2.3063
Pitch dia max (in.)2.3148
Pitch dia min (in.)2.3063
PD tolerance (in.)0.0085
Basic minor dia D1 (in.)2.2498
Minor dia max (in.)2.2668
Minor dia min (in.)2.2498
Minor dia tolerance (in.)0.0170
Major dia statusMinimum printed; maximum is a reference value (para. 3.2: PD max + 11h/9)
Minor dia statusToleranced (para. 3.2: tolerance = 2 x PD tolerance)
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)0.6876
Lead angle (deg min)0° 41′
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.)2.249800
Sweep cut: tip diameter (in.)2.362800
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-2
Mating member of the same designation2-11.5NPSH EXT
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 printedH 23/32; T 19/32; n 6 3/4
Table 4: H depth of coupling (in.)0.71875
Table 4: T thread length of coupling (in.)0.59375
Table 4: approx number of threads in T6.75000
Table 7 plug gage: GO major max (in.)2.3634
Table 7 plug gage: GO major min (in.)2.3628
Table 7 plug gage: GO pitch max (in.)2.3067
Table 7 plug gage: GO pitch min (in.)2.3063
Table 7 plug gage: NOT GO major max (in.)2.3525
Table 7 plug gage: NOT GO major min (in.)2.3519
Table 7 plug gage: NOT GO pitch max (in.)2.3148
Table 7 plug gage: NOT GO pitch min (in.)2.3144
Table 7 plug gage: Z GO minor max (in.)2.24996
Table 7 plug gage: Z GO minor min (in.)2.24980
Table 7 plug gage: Z NOT GO minor max (in.)2.26680
Table 7 plug gage: Z NOT GO minor min (in.)2.26664
Check against formulasOK
NotesMaximum major diameter, major diameter tolerance (internal) are reference values from para. 3.2; root radius and 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.