M22 × 2.5 M profile Internal Thread Specifications

M22x2.5-6H

ASMESTD: ASME B1.13MSOURCE: Table 15 · p. 35TYPE: Internal (nut/tapped hole)CLASS: 6HSERIES: M coarse (Table 4)2nd choice (Table 6, p. 9) · standard size
Major diameter
22.000 min
max 22.585 (reference)
Pitch diameter
20.376 – 20.600
min – max
Minor diameter
19.294 – 19.744
min – max
Fundamental deviation
EI 0.000
pitch 2.5 mm · position H

Thread profile

M22x2.5-6H: internal M profile with its tolerance zone, drawn to scaleD = 22.000D2 = 20.376D1 = 19.294P = 2.560°30°crest P/4 = 0.625000root P/8 = 0.312500Major dia (root)22.000 min (22.585 max ref.)Pitch dia zone (flanks)20.376 – 20.600 TD2 0.224Minor dia zone (crests)19.294 – 19.744 TD1 0.450Fundamental deviationEI = 0, position HH/80.2706333H/80.811899H/40.541266h = 5H/81.353165H2.165064thread axis, 11.000 mm below the major radius (diameters shortened)FEMALE · internal thread · M22x2.5-6H

M22x2.5-6H: solid line = maximum material profile, dashed = minimum material, hatched = tolerance zone (Figs. 8 and 9), grey dashed = basic profile (Fig. 1). Drawn to scale; values in mm, diameters shortened.

Limits of size, class 6H

DimensionBasicMaxMinTolerance
Major diameter DRoot of the internal thread; max is for tool design only22.00022.585ref.22.0000.585ref.
Pitch diameter D2Sets the fit20.37620.60020.3760.224
Minor diameter D1Crest of the internal thread (the bore)19.29419.74419.2940.450
Deviations, pitch diameter ES / EIUpper and lower deviation from the basic pitch diameter (Fig. 4)—+0.2240.000—
Deviations, minor diameter ES / EICrest diameter—+0.4500.000—

Dimensions in millimetres. Values are those of the standard (ASME B1.13M); 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, mm (Fig. 4)

Tolerance zones relative to the basic sizezero line = basic size+ above · − belowD2ES +0.224EI 0.000female pitch diaD1ES +0.450EI 0.000female minor dia (crest)

Lead, flank angle and length of engagement

Allowable lead variation ±δP
0.065 mmOver the length of engagement
Equivalent change in functional diameter δd2
0.112 mmHalf the pitch diameter tolerance
Allowable half-angle variation ±δα
1° 20′ Each 30° flank angle
Length of engagement, normal LE
10.0 – 30.0 mmShort up to / long over: see all values
Lead source: Table 17, p. 48; half-angle source: Table 18; length of engagement: Table 7

Notes

  • Table 4 note (1) For high strength structural steel fasteners only. Standard internal class, no allowance (para 5.5.2); ~ inch 2B.

Mates

M22x2.5-6H takes a thread of the same standard at the same size and pitch. The standard mating external thread is class 6g. 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

→ M22 × 1 mm→ M22 × 1.5 mm→ M22 × 2 mm→ M20 × 2.5 mm→ M24 × 1 mm→ M22 × 2.5 external→ ISO metric M22x2.5 internal
All values for M22x2.5-6Hevery column of the workbook row
All values of the workbook row M22x2.5-6H
DesignationM22x2.5-6H
Alternate designation (all capitals, para 7.2.3)M22X2.5-6H INT
Pitch in designation2.5
Thread formM
SeriesCoarse
Series nameStandard coarse pitch series (Table 4)
External / internalInternal
Class6H
Nominal sizeM22
Pitch P (mm)2.50
Basic major dia D, d (mm)22.000
Size category2nd choice (Table 6, p. 9) · standard size
Source tableTable 15
Printed page35
Thread typeM coarse (Table 4)
Tolerance position, pitch diaH
Tolerance grade, pitch dia6
Tolerance position, crest diaH
Tolerance grade, crest dia6
Fundamental deviation es / EI, pitch dia (mm)0.000
Fundamental deviation es / EI, crest dia (mm)0.000
Allowance |es| / EI (mm)0.000
Major dia max (mm)22.585
Major dia min (mm)22.000
Major dia tolerance Td (mm)0.585
Major dia statusD min toleranced; D max for reference (para 9.3.1(d), Table 15 note 2)
Basic pitch dia D2, d2 (mm)20.376
Pitch dia max (mm)20.600
Pitch dia min (mm)20.376
PD tolerance Td2 / TD2 (mm)0.224
Basic minor dia D1, d1 (mm)19.294
Minor dia max (mm)19.744
Minor dia min (mm)19.294
Minor dia tolerance TD1 (mm)0.450
Minor dia statusToleranced (D1 min, D1 max)
Upper deviation, pitch dia es / ES (mm)0.224
Lower deviation, pitch dia ei / EI (mm)0.000
Upper deviation, crest dia (mm)0.450
Lower deviation, crest dia (mm)0.000
LE short, up to (mm)10.0
LE normal, over (mm)10.0
LE normal, up to and incl. (mm)30.0
LE long, over (mm)30.0
LE sourceTable 7
Lead variation ± (mm)0.065
Equivalent change in functional dia (mm)0.112
Lead values sourceTable 17, p. 48
Half-angle variation ±1° 20′
Half-angle sourceTable 18
Lead angle at basic PD (deg)2.2365
Lead angle (deg min)2° 14′
Thread angle (deg)60
Flank angle (deg)30
Sharp V height H (mm)2.165064
Thread height h = 5H/8 (mm)1.353165
Crest flat (mm)0.625000
Root flat (mm)0.312500
Sweep cut: start diameter (mm)19.294000
Sweep cut: tip diameter (mm)22.000000
Sweep cut: depth (mm)1.353000
Sweep cut: profile width at start diameter (mm)1.874693
Crest flat as modelled (mm)0.625307
Inch (App. C): allowance (in.)0.00000
Inch (App. C): major dia min (in.)0.86614
Inch (App. C): pitch dia max (in.)0.81102
Inch (App. C): pitch dia min (in.)0.80220
Inch (App. C): PD tolerance (in.)0.00882
Inch (App. C): minor dia max (in.)0.77732
Inch (App. C): minor dia min (in.)0.75961
Inch (App. C): d3 min / D max, reference (in.)0.88917
Inch (App. C): pitch (in.)0.09843
Inch (App. C): printed page62
Check against formulasOK: all 7 printed Table 15 values agree with the formulas.
NotesTable 4 note (1) For high strength structural steel fasteners only. Standard internal class, no allowance (para 5.5.2); ~ inch 2B.

Related tools

ASME B1.13M: Metric Screw Threads: M Profile. Source: workbook data (2026-10-10). Confirm against your licensed copy of the standard before use.