UNEF — Unified extra-fine

#12-32 UNEF

Tap drill #13 for a #12-32 UNEF thread — major Ø 5.486 mm, pitch 0.794 mm (32 TPI).

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Tap drill

#13

4.7 mm · ≈76% thread

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Thread form & key diameters

Dimensions

Designation	#12-32 UNEF
Major (outside) diameter	5.486 mm · 0.216"
Pitch	0.794 mm · 32 TPI
Pitch diameter	4.971 mm · 0.1957"
Minor diameter (external)	4.513 mm · 0.1777"
Minor diameter (internal)	4.627 mm · 0.1822"
Recommended tap drill	#13 · 4.7 mm · ≈76% thread
Clearance hole	Close A · Normal D · Loose J — nominal + 1/64" / 1/32" / 1/16" to the nearest standard drill (common shop practice).

Close A · Normal D · Loose J — nominal + 1/64" / 1/32" / 1/16" to the nearest standard drill (common shop practice).

What tap drill do I need for #12-32 UNEF?

For a #12-32 UNEF thread, drill the hole with a #13 tap drill (4.7 mm) before tapping. That produces roughly 76% thread engagement, the usual target for a strong, tappable hole. The mating bolt has a major diameter of 5.486 mm and a pitch of 0.794 mm (32 TPI).

To pass a #12-32 UNEF bolt through a part rather than thread it, use a clearance hole: Close A · Normal D · Loose J — nominal + 1/64" / 1/32" / 1/16" to the nearest standard drill (common shop practice)..

All values are generated from the standard thread formulas (ISO 68-1 / ASME B1.1) and published standard tables — not hand-entered. See the full reference.

Same diameter

Other #12 threads

#12-28 UNFTap #14Ø 5.486 mm · pitch 0.907 mm #12-24 UNCTap #16Ø 5.486 mm · pitch 1.058 mm

Nearby sizes

More unef — unified extra-fine threads

1/4-32 UNEFTap 7/32"Ø 6.35 mm · pitch 0.794 mm 5/16-32 UNEFTap 9/32"Ø 7.938 mm · pitch 0.794 mm 3/8-32 UNEFTap 11/32"Ø 9.525 mm · pitch 0.794 mm 7/16-28 UNEFTap YØ 11.112 mm · pitch 0.907 mm 1/2-28 UNEFTap 15/32"Ø 12.7 mm · pitch 0.907 mm 9/16-24 UNEFTap 33/64"Ø 14.288 mm · pitch 1.058 mm 5/8-24 UNEFTap 37/64"Ø 15.875 mm · pitch 1.058 mm 3/4-20 UNEFTap 45/64"Ø 19.05 mm · pitch 1.27 mm