letter drill · nominal diameter

A
drill bit size.

A A bit measures 0.2340 in across (5.944 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

A · letter

0.2340 in

5.944 mm

DesignationAletter

Inch decimal0.2340nominal

Metric conversion5.944millimetres

Where this size sits from 0 to 1 inch

A · 5.944 mm on a zero to 25.4 millimetre scale. Neighbor marks: 15/64, 5.9 mm.

0 25.4 mm

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Measured neighbors

What sits beside A.

“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

15/64fractional 0.2344 inΔ +0.010 mm 5.9 mmmetric 0.2323 inΔ -0.044 mm 6 mmmetric 0.2362 inΔ +0.056 mm 5.8 mmmetric 0.2283 inΔ -0.144 mm #1number 0.2280 inΔ -0.152 mm

Same seriesNEAREST NOMINAL ROWS

Bletter 6.045 mmΔ +0.102 mm Cletter 6.147 mmΔ +0.203 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

Adrill bit size.

What sits beside A.

ASME.

A
drill bit size.