metric comparison size · nominal diameter
7.8 mm
drill bit size.
A 7.8 mm bit measures 0.3071 in across (7.800 mm).
The metric diameter is the generated reference value; inches are a conversion. Commercial set contents vary.
Calibrated relative diameter · 1 in reference
7.8 mm · metric
0.3071 in
7.800 mm Designation7.8 mmmetric
Inch decimal0.3071nominal
Metric conversion7.800millimetres
Where this size sits from 0 to 1 inch 7.8 mm · 7.800 mm on a zero to 25.4 millimetre scale. Neighbor marks: 7.7 mm, 7.9 mm.
Measured neighbors
What sits beside 7.8 mm.
“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.
Source record
Drill Bit Size Chart.
A generated comparison series from 0.5 to 13.0 mm in 0.1 mm steps. It is not a claim that every size is included in every commercial set.
Open source record