number drill · nominal diameter

#42
drill bit size.

A #42 bit measures 0.0935 in across (2.375 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#42 · number

0.0935 in

2.375 mm

Designation#42number

Inch decimal0.0935nominal

Metric conversion2.375millimetres

Where this size sits from 0 to 1 inch

#42 · 2.375 mm on a zero to 25.4 millimetre scale. Neighbor marks: 3/32, 2.4 mm.

0 25.4 mm

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Where this bit is specified

What #42 is for.

#42 is the cutting-tap drill for the thread below— usually the reason this size gets looked up. Engagement is calculated from the basic 60° profile; open a thread for its published row, evidence, and limits.

Cutting-tap rows naming #42 CUT TAPS ONLY · CALCULATED ENGAGEMENT

#4-48 UNF UNF · rule-of-thumb row 68.4% calculated thread engagement

Measured neighbors

What sits beside #42.

“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

3/32fractional 0.0938 inΔ +0.006 mm 2.4 mmmetric 0.0945 inΔ +0.025 mm 2.3 mmmetric 0.0906 inΔ -0.075 mm 2.5 mmmetric 0.0984 inΔ +0.125 mm

Same seriesNEAREST NOMINAL ROWS

#41number 2.438 mmΔ +0.064 mm #43number 2.261 mmΔ -0.114 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

#42drill bit size.

What #42 is for.

What sits beside #42.

ASME.

#42
drill bit size.