letter drill · nominal diameter

J
drill bit size.

A J bit measures 0.2770 in across (7.036 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

J · letter

0.2770 in

7.036 mm

DesignationJletter

Inch decimal0.2770nominal

Metric conversion7.036millimetres

Where this size sits from 0 to 1 inch

J · 7.036 mm on a zero to 25.4 millimetre scale. Neighbor marks: 7 mm, 7.1 mm.

0 25.4 mm

Show calibrated outline Open in Finder

Measured neighbors

What sits beside J.

“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

7 mmmetric 0.2756 inΔ -0.036 mm 7.1 mmmetric 0.2795 inΔ +0.064 mm 9/32fractional 0.2813 inΔ +0.108 mm 6.9 mmmetric 0.2717 inΔ -0.136 mm 7.2 mmmetric 0.2835 inΔ +0.164 mm

Same seriesNEAREST NOMINAL ROWS

Kletter 7.137 mmΔ +0.102 mm Iletter 6.909 mmΔ -0.127 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

Jdrill bit size.

What sits beside J.

ASME.

J
drill bit size.