letter drill · nominal diameter

Z
drill bit size.

A Z bit measures 0.4130 in across (10.490 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

Z · letter

0.4130 in

10.490 mm

DesignationZletter

Inch decimal0.4130nominal

Metric conversion10.490millimetres

Where this size sits from 0 to 1 inch

Z · 10.490 mm on a zero to 25.4 millimetre scale. Neighbor marks: 10.5 mm, 10.4 mm.

0 25.4 mm

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Measured neighbors

What sits beside Z.

“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

10.5 mmmetric 0.4134 inΔ +0.010 mm 10.4 mmmetric 0.4094 inΔ -0.090 mm 10.6 mmmetric 0.4173 inΔ +0.110 mm 13/32fractional 0.4063 inΔ -0.171 mm 10.3 mmmetric 0.4055 inΔ -0.190 mm

Same seriesNEAREST NOMINAL ROWS

Yletter 10.262 mmΔ -0.229 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

Zdrill bit size.

What sits beside Z.

ASME.

Z
drill bit size.