number drill · nominal diameter

#5
drill bit size.

A #5 bit measures 0.2055 in across (5.220 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#5 · number

0.2055 in

5.220 mm

Designation#5number

Inch decimal0.2055nominal

Metric conversion5.220millimetres

Where this size sits from 0 to 1 inch

#5 · 5.220 mm on a zero to 25.4 millimetre scale. Neighbor marks: 5.2 mm, #6.

0 25.4 mm

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Measured neighbors

What sits beside #5.

“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

5.2 mmmetric 0.2047 inΔ -0.020 mm 13/64fractional 0.2031 inΔ -0.060 mm 5.3 mmmetric 0.2087 inΔ +0.080 mm 5.1 mmmetric 0.2008 inΔ -0.120 mm

Same seriesNEAREST NOMINAL ROWS

#6number 5.182 mmΔ -0.038 mm #4number 5.309 mmΔ +0.089 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

#5drill bit size.

What sits beside #5.

ASME.

#5
drill bit size.