letter drill · nominal diameter

H
drill bit size.

A H bit measures 0.2660 in across (6.756 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

H · letter

0.2660 in

6.756 mm

DesignationHletter

Inch decimal0.2660nominal

Metric conversion6.756millimetres

Where this size sits from 0 to 1 inch

H · 6.756 mm on a zero to 25.4 millimetre scale. Neighbor marks: 17/64, 6.8 mm.

0 25.4 mm

Show calibrated outline Open in Finder

Measured neighbors

What sits beside H.

“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

17/64fractional 0.2656 inΔ -0.010 mm 6.8 mmmetric 0.2677 inΔ +0.044 mm 6.7 mmmetric 0.2638 inΔ -0.056 mm 6.9 mmmetric 0.2717 inΔ +0.144 mm 6.6 mmmetric 0.2598 inΔ -0.156 mm

Same seriesNEAREST NOMINAL ROWS

Gletter 6.629 mmΔ -0.127 mm Iletter 6.909 mmΔ +0.152 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

Hdrill bit size.

What sits beside H.

ASME.

H
drill bit size.