#7 drill bit — 5.105 mm
The #7 bit measures 5.105 mm (0.201 in). The closest bits in the other series are 5.2, 13/64, A.
- Diameter
- 5.105 mm
- In inches
- 0.201 in
- Cross-section
- 20.47 mm²
Closest in other series
Use this when the only bits at hand belong to another series. For tapping, prefer the slightly smaller bit over the slightly larger one — a hole can be opened up later, never closed.
Threads this bit taps
A tap drill is the thread’s outside diameter minus its pitch, which lands between the round numbers: 2.5 mm for M3, 3.3 for M4, 6.8 for M8. That is exactly why drill sets carry those odd sizes.
One step up and down
number
Metric bits state the millimetres outright, inch bits state sixty-fourths. Number and letter bits carry names inherited from old wire gauges, where no formula links the label to the size.
How to read this
- Inch bits are counted in sixty-fourths — 16/64 reduces to 1/4.
- Higher numbers are thinner; later letters are thicker, with A picking up above #1.
- An inch is 25.4 mm, so multiply the inch value by 25.4 to get millimetres.
- For tapping, drill with the bit nearest to the thread’s outside diameter minus its pitch.
Frequently asked questions
Q. How wide is the #7 bit?
5.105 mm, or 0.201 inches.
Q. What would I use from another series?
The closest are 5.2 (5.2 mm), 13/64 (5.159 mm), A (5.944 mm).
Q. Which threads can this size tap?
M6×1 (tap drill 5 mm), M6×0.75 (tap drill 5.25 mm).
Q. What is the cross-section?
20.47 mm².