M42 × 4.5 M profile External Thread Specifications
M42x4.5-6g
ASMESTD: ASME B1.13MSOURCE: Table 14 · p. 30TYPE: External (bolt/screw)CLASS: 6gSERIES: M coarse (Table 4)1st choice (Table 6, p. 10) · standard size
Major diameter
41.937 – 41.437
max – min
Pitch diameter
39.014 – 38.778
max – min
Minor diameter
37.065 – 36.006
max – min (min is a reference value)
Fundamental deviation
es −0.063
pitch 4.5 mm · position g
Thread profile
M42x4.5-6g: 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 6g
| Dimension | Basic | Max | Min | Tolerance |
|---|---|---|---|---|
| Major diameter dOutside diameter over the crests | 42.000 | 41.937 | 41.437 | 0.500 |
| Pitch diameter d2Where thread and groove widths are equal; sets the fit | 39.077 | 39.014 | 38.778 | 0.236 |
| Minor diameter, flat root d1Max d1 (flat form); min = d3 of the rounded form, for reference | 37.129 | 37.065 | 36.006ref. | 1.059ref. |
| Rounded-form minor diameter d3d3 max and d3 min; used for tools and gaging | 36.878ref. | 36.006ref. | ||
| Deviations, pitch diameter es / eiUpper and lower deviation from the basic pitch diameter (Fig. 4) | — | −0.063 | −0.299 | — |
| Deviations, major diameter es / eiCrest diameter | — | −0.063 | −0.563 | — |
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)
Lead, flank angle and length of engagement
- Allowable lead variation ±δP
- 0.068 mmOver the length of engagement
- Equivalent change in functional diameter δd2
- 0.118 mmHalf the pitch diameter tolerance
- Allowable half-angle variation ±δα
- 1° 00′ Each 30° flank angle
- Length of engagement, normal LE
- 21.0 – 63.0 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
- Normal tolerance, small allowance (para 5.5.1(a)); the usual bolt class, ~ inch 2A.
Mates
M42x4.5-6g screws into a thread of the same standard at the same size and pitch. The standard mating internal thread is class 6H. 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
All values for M42x4.5-6gevery column of the workbook row
| Designation | M42x4.5-6g |
|---|---|
| Alternate designation (all capitals, para 7.2.3) | M42X4.5-6G EXT |
| Pitch in designation | 4.5 |
| Thread form | M |
| Series | Coarse |
| Series name | Standard coarse pitch series (Table 4) |
| External / internal | External |
| Class | 6g |
| Nominal size | M42 |
| Pitch P (mm) | 4.50 |
| Basic major dia D, d (mm) | 42.000 |
| Size category | 1st choice (Table 6, p. 10) · standard size |
| Source table | Table 14 |
| Printed page | 30 |
| Thread type | M coarse (Table 4) |
| Tolerance position, pitch dia | g |
| Tolerance grade, pitch dia | 6 |
| Tolerance position, crest dia | g |
| Tolerance grade, crest dia | 6 |
| Fundamental deviation es / EI, pitch dia (mm) | -0.063 |
| Fundamental deviation es / EI, crest dia (mm) | -0.063 |
| Allowance |es| / EI (mm) | 0.063 |
| Major dia max (mm) | 41.937 |
| Major dia min (mm) | 41.437 |
| Major dia tolerance Td (mm) | 0.500 |
| Major dia status | Toleranced (d max, d min) |
| Basic pitch dia D2, d2 (mm) | 39.077 |
| Pitch dia max (mm) | 39.014 |
| Pitch dia min (mm) | 38.778 |
| PD tolerance Td2 / TD2 (mm) | 0.236 |
| Basic minor dia D1, d1 (mm) | 37.129 |
| Minor dia max (mm) | 37.065 |
| Minor dia min (mm) | 36.006 |
| Minor dia tolerance TD1 (mm) | 1.059 |
| Minor dia status | d1 max toleranced (flat form, para 9.3.2(e)); min is d3 min of the rounded form, for reference (Table 14 note 4) |
| Max minor dia, flat form d1 (mm) | 37.065 |
| Min minor dia, rounded form d3 (mm, reference) | 36.006 |
| Max minor dia, rounded form d3, para 9.3.2(f) (mm) | 36.878 |
| Upper deviation, pitch dia es / ES (mm) | -0.063 |
| Lower deviation, pitch dia ei / EI (mm) | -0.299 |
| Upper deviation, crest dia (mm) | -0.063 |
| Lower deviation, crest dia (mm) | -0.563 |
| LE short, up to (mm) | 21.0 |
| LE normal, over (mm) | 21.0 |
| LE normal, up to and incl. (mm) | 63.0 |
| LE long, over (mm) | 63.0 |
| LE source | Table 7 |
| Lead variation ± (mm) | 0.068 |
| Equivalent change in functional dia (mm) | 0.118 |
| Lead values source | Table 17, p. 48 |
| Half-angle variation ± | 1° 00′ |
| Half-angle source | Table 18 |
| Lead angle at basic PD (deg) | 2.0993 |
| Lead angle (deg min) | 2° 06′ |
| Tensile stress area As (mm²) | 1120.911 |
| Thread angle (deg) | 60 |
| Flank angle (deg) | 30 |
| Sharp V height H (mm) | 3.897114 |
| Thread height h = 5H/8 (mm) | 2.435697 |
| Crest flat (mm) | 0.562500 |
| Root flat (mm) | 1.125000 |
| Sweep cut: start diameter (mm) | 41.937000 |
| Sweep cut: tip diameter (mm) | 37.065000 |
| Sweep cut: depth (mm) | 2.436000 |
| Sweep cut: profile width at start diameter (mm) | 3.937500 |
| Crest flat as modelled (mm) | 0.562405 |
| Inch (App. C): allowance (in.) | 0.00248 |
| Inch (App. C): major dia max (in.) | 1.65106 |
| Inch (App. C): major dia min (in.) | 1.63138 |
| Inch (App. C): pitch dia max (in.) | 1.53598 |
| Inch (App. C): pitch dia min (in.) | 1.52669 |
| Inch (App. C): PD tolerance (in.) | 0.00929 |
| Inch (App. C): minor dia max (in.) | 1.45925 |
| Inch (App. C): d3 min / D max, reference (in.) | 1.41756 |
| Inch (App. C): pitch (in.) | 0.17717 |
| Inch (App. C): printed page | 57 |
| Check against formulas | OK: all 8 printed Table 14 values agree with the formulas. |
| Notes | Normal tolerance, small allowance (para 5.5.1(a)); the usual bolt class, ~ inch 2A. |
Related tools
- Thread standardsEvery ISO and ASME thread series and size, with limits and drawings.
- Thread Spec CalculatorDiameters, tolerances and geometry for ISO metric and unified threads.
- Thread Fit CheckPick a bolt and a nut and see the clearance or interference.
- Twist Drill SizesASME B94.11M drills: sizes, lengths, shanks and tolerances.
- Thread Designation GuideHow to read M10×1.5, 1/4-20 UNC-2A, NPT and more.
- Thread Notations & TermsSymbols and terms of a thread profile, explained.
ASME B1.13M: Metric Screw Threads: M Profile. Source: workbook data (2026-10-10). Confirm against your licensed copy of the standard before use.