number drill · nominal diameter

#43
drill bit size.

A #43 bit measures 0.0890 in across (2.261 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#43 · number

0.0890 in

2.261 mm

Designation#43number

Inch decimal0.0890nominal

Metric conversion2.261millimetres

Where this size sits from 0 to 1 inch

#43 · 2.261 mm on a zero to 25.4 millimetre scale. Neighbor marks: 2.3 mm, 2.2 mm.

0 25.4 mm

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Where this bit is specified

What #43 is for.

#43 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 #43 CUT TAPS ONLY · CALCULATED ENGAGEMENT

#4-40 UNC UNC · rule-of-thumb row 70.8% calculated thread engagement

Measured neighbors

What sits beside #43.

“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

2.3 mmmetric 0.0906 inΔ +0.039 mm 2.2 mmmetric 0.0866 inΔ -0.061 mm 3/32fractional 0.0938 inΔ +0.121 mm 2.4 mmmetric 0.0945 inΔ +0.139 mm 2.1 mmmetric 0.0827 inΔ -0.161 mm

Same seriesNEAREST NOMINAL ROWS

#44number 2.184 mmΔ -0.076 mm #42number 2.375 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

#43drill bit size.

What #43 is for.

What sits beside #43.

ASME.

#43
drill bit size.