Threads / Size reference

3/8-32 UNEF

3/8-32 has a nominal outside diameter of 9.525 mm and a 0.79375 mm pitch.

Nominal major diameter0.375 in

9.525 mm

Threads per inch32 TPI

0.79375 mm pitch

Nominal dimensions; no class allowances or acceptance limits applied. Diameter is in inches; the number after the dash is TPI.

3/8-32 · PITCH VIEWSCHEMATIC
PP = 0.79375 mm · 32 TPI

same diameter comparison

3/8-32 vs 3/8-24

3/8-24 UNF shares the nominal diameter but has a 1.058333 mm pitch. The pitch difference is 0.264583 mm; these are different nominal threads.

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Nominal size comparison
Property3/8-32 UNEF3/8-24 UNF
Nominal diameter · in0.3750.375
Nominal diameter · mm9.5259.525
Threads per inchDifferent3224
Pitch · mmDifferent0.793751.058333
All 3 options at this diameter

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Nominal thread sizes in this reference
DesignationMajor Ø · in / mmTPIPitch · mmDrill evidenceNext step
3/8-16 UNC0.375 / 9.525161.5875Chart rowTap-drill lookup →
3/8-24 UNF0.375 / 9.525241.058333Chart rowTap-drill lookup →
3/8-32 UNEF0.375 / 9.525320.79375Maker data neededTap-drill lookup →
Tap-maker data needed

Tapping-hole evidence for 3/8-32

No reviewed chart row for 3/8-32 UNEF

No UNEF drill row or UNEF-specific equation scope has been reviewed. Use the exact tap maker’s data; a UNC/UNF drill at the same diameter is not a substitute.

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.

ASME B1.1 · standard scope ↗ · Full source scope →