Threads / Size reference

M18x2 Metric fine

M18x2 has a nominal outside diameter of 18 mm and a 2 mm pitch.

Nominal major diameter18 mm

0.708661 in

Pitch2 mm

12.7 TPI · calculated

Nominal dimensions; no class allowances or acceptance limits applied. M sizes state diameter and pitch in millimetres.

M18x2 · PITCH VIEWSCHEMATIC
PP = 2 mm

same diameter comparison

M18x2 vs M18x1.5

M18x1.5 Metric fine shares the nominal diameter but has a 1.500000 mm pitch. The pitch difference is 0.500000 mm; these are different nominal threads.

Swipe to compare both sizes →

Nominal size comparison
PropertyM18x2 Metric fineM18x1.5 Metric fine
Nominal diameter · in0.7086610.708661
Nominal diameter · mm1818
Threads per inchDifferent12.716.933333
Pitch · mmDifferent21.5
Equation estimate only

Tapping-hole evidence for M18x2

No reviewed chart row for M18x2 Metric fine

You can calculate a theoretical hole with the cited equation. It is not a stocked-drill selection or a tool-specific hole range.

Need acceptance limits?

The complete class and applicable drawing requirements are needed. These nominal values are not maximum/minimum inspection limits.

Part has no marking?

Measure the correct diameter and pitch, then compare candidates across metric and inch systems.

Basis for this size

Nominal designation and family transcribed from the live directory on 2026-10-19; unit conversions are calculated using exactly 25.4 mm/in. No matching drill row has been reviewed for this exact size. Paid standard limit tables have not been reviewed.

ISO 261 · metric general plan ↗ · Guhring · Tap Drill Sizes ↗ Full source scope →