Threads / Size reference

M42x3 Metric fine

M42x3 has a nominal outside diameter of 42 mm and a 3 mm pitch.

Nominal major diameter42 mm

1.653543 in

Pitch3 mm

8.466667 TPI · calculated

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

M42x3 · PITCH VIEWSCHEMATIC
PP = 3 mm

same diameter comparison

M42x3 vs M42x4.5

M42x4.5 Metric coarse shares the nominal diameter but has a 4.500000 mm pitch. The pitch difference is 1.500000 mm; these are different nominal threads.

Swipe to compare both sizes →

Nominal size comparison
PropertyM42x3 Metric fineM42x4.5 Metric coarse
Nominal diameter · in1.6535431.653543
Nominal diameter · mm4242
Threads per inchDifferent8.4666675.644444
Pitch · mmDifferent34.5
Equation estimate only

Tapping-hole evidence for M42x3

No reviewed chart row for M42x3 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 →