number drill · nominal diameter

#22
drill bit size.

A #22 bit measures 0.1570 in across (3.988 mm).

The inch decimal is the published nominal designation; millimetres are a conversion.

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#22 · number

0.1570 in

3.988 mm

Designation#22number

Inch decimal0.1570nominal

Metric conversion3.988millimetres

Where this size sits from 0 to 1 inch

#22 · 3.988 mm on a zero to 25.4 millimetre scale. Neighbor marks: 4 mm, 5/32.

0 25.4 mm

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Measured neighbors

What sits beside #22.

“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.

Other naming systemsABSOLUTE DIAMETER DELTA

4 mmmetric 0.1575 inΔ +0.012 mm 5/32fractional 0.1563 inΔ -0.019 mm 3.9 mmmetric 0.1535 inΔ -0.088 mm 4.1 mmmetric 0.1614 inΔ +0.112 mm

Same seriesNEAREST NOMINAL ROWS

#21number 4.039 mmΔ +0.051 mm #23number 3.912 mmΔ -0.076 mm

Source record

ASME.

The standard text is paywalled. Number and letter series are cross-checked against public manufacturer charts; exact standard edition/page verification remains a release gate.

Open source record

#22drill bit size.

What sits beside #22.

ASME.

#22
drill bit size.