number drill · nominal diameter

#56
drill bit size.

A #56 bit measures 0.0465 in across (1.181 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#56 · number

0.0465 in

1.181 mm

Designation#56number

Inch decimal0.0465nominal

Metric conversion1.181millimetres

Where this size sits from 0 to 1 inch

#56 · 1.181 mm on a zero to 25.4 millimetre scale. Neighbor marks: 3/64, 1.2 mm.

0 25.4 mm

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Measured neighbors

What sits beside #56.

“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

3/64fractional 0.0469 inΔ +0.010 mm 1.2 mmmetric 0.0472 inΔ +0.019 mm 1.1 mmmetric 0.0433 inΔ -0.081 mm 1.3 mmmetric 0.0512 inΔ +0.119 mm

Same seriesNEAREST NOMINAL ROWS

#57number 1.092 mmΔ -0.089 mm #58number 1.067 mmΔ -0.114 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

#56drill bit size.

What sits beside #56.

ASME.

#56
drill bit size.