Coarse and fine pitch series with pitch, pitch diameter and minor diameters from M1 to M64.
Metric is the default thread system on Indian drawings, and almost every thread gauge DSN manufactures is cut to it. The tables below cover the ISO 261 coarse series and the fine pitches that are actually specified in practice, with the basic dimensions derived from the ISO 68-1 profile.
Basic dimensions to ISO 68-1 / ISO 261 / ISO 965, adopted in India as IS 919 / IS 4218. Thread angle 60°.
| Size | Pitchmm | Pitch Ømm | Minor Ø ext.mm | Minor Ø int.mm | Tap drillmm | A/Fmm |
|---|---|---|---|---|---|---|
| M1 | 0.25 | 0.838 | 0.693 | 0.729 | 0.75 | — |
| M1.2 | 0.25 | 1.038 | 0.893 | 0.929 | 0.95 | — |
| M1.4 | 0.3 | 1.205 | 1.032 | 1.075 | 1.1 | — |
| M1.6 | 0.35 | 1.373 | 1.171 | 1.221 | 1.25 | — |
| M1.8 | 0.35 | 1.573 | 1.371 | 1.421 | 1.45 | — |
| M2 | 0.4 | 1.74 | 1.509 | 1.567 | 1.6 | — |
| M2.2 | 0.45 | 1.908 | 1.648 | 1.713 | 1.75 | — |
| M2.5 | 0.45 | 2.208 | 1.948 | 2.013 | 2.05 | — |
| M3 | 0.5 | 2.675 | 2.387 | 2.459 | 2.5 | 5.5 |
| M3.5 | 0.6 | 3.11 | 2.764 | 2.85 | 2.9 | — |
| M4 | 0.7 | 3.545 | 3.141 | 3.242 | 3.3 | 7 |
| M5 | 0.8 | 4.48 | 4.019 | 4.134 | 4.2 | 8 |
| M6 | 1 | 5.35 | 4.773 | 4.917 | 5 | 10 |
| M7 | 1 | 6.35 | 5.773 | 5.917 | 6 | — |
| M8 | 1.25 | 7.188 | 6.466 | 6.647 | 6.75 | 13 |
| M10 | 1.5 | 9.026 | 8.16 | 8.376 | 8.5 | 16 |
| M12 | 1.75 | 10.863 | 9.853 | 10.106 | 10.25 | 18 |
| M14 | 2 | 12.701 | 11.546 | 11.835 | 12 | 21 |
| M16 | 2 | 14.701 | 13.546 | 13.835 | 14 | 24 |
| M18 | 2.5 | 16.376 | 14.933 | 15.294 | 15.5 | 27 |
| M20 | 2.5 | 18.376 | 16.933 | 17.294 | 17.5 | 30 |
| M22 | 2.5 | 20.376 | 18.933 | 19.294 | 19.5 | 32 |
| M24 | 3 | 22.051 | 20.319 | 20.752 | 21 | 36 |
| M27 | 3 | 25.051 | 23.319 | 23.752 | 24 | 41 |
| M30 | 3.5 | 27.727 | 25.706 | 26.211 | 26.5 | 46 |
| M33 | 3.5 | 30.727 | 28.706 | 29.211 | 29.5 | 50 |
| M36 | 4 | 33.402 | 31.093 | 31.67 | 32 | 55 |
| M39 | 4 | 36.402 | 34.093 | 34.67 | 35 | 60 |
| M42 | 4.5 | 39.077 | 36.479 | 37.129 | 37.5 | 65 |
| M45 | 4.5 | 42.077 | 39.479 | 40.129 | 40.5 | 70 |
| M48 | 5 | 44.752 | 41.866 | 42.587 | 43 | 75 |
| M52 | 5 | 48.752 | 45.866 | 46.587 | 47 | 80 |
| M56 | 5.5 | 52.428 | 49.252 | 50.046 | 50.5 | 85 |
| M60 | 5.5 | 56.428 | 53.252 | 54.046 | 54.5 | 90 |
| M64 | 6 | 60.103 | 56.639 | 57.505 | 58 | 95 |
Detailed pages for the metric sizes specified most often on Indian drawings, each with the coarse and fine series and the tap drill for that size.
Fine pitches below the coarse series. Both columns of minor diameters are given because an external thread and an internal thread of the same designation do not share one.
| Designation | Pitchmm | Pitch Ømm | Minor Ø ext.mm | Minor Ø int.mm | Tap drillmm |
|---|---|---|---|---|---|
| M3x0.35 | 0.35 | 2.773 | 2.571 | 2.621 | 2.65 |
| M4x0.5 | 0.5 | 3.675 | 3.387 | 3.459 | 3.5 |
| M5x0.5 | 0.5 | 4.675 | 4.387 | 4.459 | 4.5 |
| M6x0.75 | 0.75 | 5.513 | 5.08 | 5.188 | 5.25 |
| M8x0.75 | 0.75 | 7.513 | 7.08 | 7.188 | 7.25 |
| M8x1 | 1 | 7.35 | 6.773 | 6.917 | 7 |
| M10x0.75 | 0.75 | 9.513 | 9.08 | 9.188 | 9.25 |
| M10x1 | 1 | 9.35 | 8.773 | 8.917 | 9 |
| M10x1.25 | 1.25 | 9.188 | 8.466 | 8.647 | 8.75 |
| M12x1 | 1 | 11.35 | 10.773 | 10.917 | 11 |
| M12x1.25 | 1.25 | 11.188 | 10.466 | 10.647 | 10.75 |
| M12x1.5 | 1.5 | 11.026 | 10.16 | 10.376 | 10.5 |
| M14x1 | 1 | 13.35 | 12.773 | 12.917 | 13 |
| M14x1.25 | 1.25 | 13.188 | 12.466 | 12.647 | 12.75 |
| M14x1.5 | 1.5 | 13.026 | 12.16 | 12.376 | 12.5 |
| M16x1 | 1 | 15.35 | 14.773 | 14.917 | 15 |
| M16x1.5 | 1.5 | 15.026 | 14.16 | 14.376 | 14.5 |
| M18x1 | 1 | 17.35 | 16.773 | 16.917 | 17 |
| M18x1.5 | 1.5 | 17.026 | 16.16 | 16.376 | 16.5 |
| M18x2 | 2 | 16.701 | 15.546 | 15.835 | 16 |
| M20x1 | 1 | 19.35 | 18.773 | 18.917 | 19 |
| M20x1.5 | 1.5 | 19.026 | 18.16 | 18.376 | 18.5 |
| M20x2 | 2 | 18.701 | 17.546 | 17.835 | 18 |
| M22x1 | 1 | 21.35 | 20.773 | 20.917 | 21 |
| M22x1.5 | 1.5 | 21.026 | 20.16 | 20.376 | 20.5 |
| M22x2 | 2 | 20.701 | 19.546 | 19.835 | 20 |
| M24x1.5 | 1.5 | 23.026 | 22.16 | 22.376 | 22.5 |
| M24x2 | 2 | 22.701 | 21.546 | 21.835 | 22 |
| M27x1.5 | 1.5 | 26.026 | 25.16 | 25.376 | 25.5 |
| M27x2 | 2 | 25.701 | 24.546 | 24.835 | 25 |
| M27x3 | 3 | 25.051 | 23.319 | 23.752 | 24 |
| M30x1.5 | 1.5 | 29.026 | 28.16 | 28.376 | 28.5 |
| M30x2 | 2 | 28.701 | 27.546 | 27.835 | 28 |
| M30x3 | 3 | 28.051 | 26.319 | 26.752 | 27 |
| M33x1.5 | 1.5 | 32.026 | 31.16 | 31.376 | 31.5 |
| M33x2 | 2 | 31.701 | 30.546 | 30.835 | 31 |
| M33x3 | 3 | 31.051 | 29.319 | 29.752 | 30 |
| M36x1.5 | 1.5 | 35.026 | 34.16 | 34.376 | 34.5 |
| M36x2 | 2 | 34.701 | 33.546 | 33.835 | 34 |
| M36x3 | 3 | 34.051 | 32.319 | 32.752 | 33 |
| M39x2 | 2 | 37.701 | 36.546 | 36.835 | 37 |
| M39x3 | 3 | 37.051 | 35.319 | 35.752 | 36 |
| M42x2 | 2 | 40.701 | 39.546 | 39.835 | 40 |
| M42x3 | 3 | 40.051 | 38.319 | 38.752 | 39 |
| M42x4 | 4 | 39.402 | 37.093 | 37.67 | 38 |
| M45x2 | 2 | 43.701 | 42.546 | 42.835 | 43 |
| M45x3 | 3 | 43.051 | 41.319 | 41.752 | 42 |
| M45x4 | 4 | 42.402 | 40.093 | 40.67 | 41 |
| M48x2 | 2 | 46.701 | 45.546 | 45.835 | 46 |
| M48x3 | 3 | 46.051 | 44.319 | 44.752 | 45 |
| M48x4 | 4 | 45.402 | 43.093 | 43.67 | 44 |
| M52x3 | 3 | 50.051 | 48.319 | 48.752 | 49 |
| M52x4 | 4 | 49.402 | 47.093 | 47.67 | 48 |
| M56x3 | 3 | 54.051 | 52.319 | 52.752 | 53 |
| M56x4 | 4 | 53.402 | 51.093 | 51.67 | 52 |
| M60x3 | 3 | 58.051 | 56.319 | 56.752 | 57 |
| M60x4 | 4 | 57.402 | 55.093 | 55.67 | 56 |
| M64x3 | 3 | 62.051 | 60.319 | 60.752 | 61 |
| M64x4 | 4 | 61.402 | 59.093 | 59.67 | 60 |
Internal threads are checked with a thread plug gauge — a matched GO / NO-GO pair — and external threads with a thread ring gauge or a calibrated snap gauge. Setting plugs keep the rings in calibration between recertifications.
DSN manufactures ISO Metric plug gauges, ring gauges and setting plugs at the Coimbatore works, cut and lapped as matched pairs and issued with traceable calibration certificates. Send a drawing or a thread designation and we will quote to it.