#6 drill size
A #6 drill is 0.2040 in (5.18 mm). It sits between #7 and #5 in the number series; the nearest metric drill is 5.2 mm.
#6 at a glance
Decimal, metric and the nearest sizes in the other series.
Nearest metric drills
Metric drills step by 0.05 mm below 3 mm and by 0.1 mm from 3 mm. Difference is metric minus inch size.
| Metric drill | Inch | Difference | In inches | Hole |
|---|---|---|---|---|
| 5.1 mm | 0.2008" | −0.082 mm | −0.0032" | Smaller |
| 5.2 mm | 0.2047" | +0.018 mm | +0.0007" | Larger |
Nearby inch drills
The next size down and up in each inch series, so you can pick a substitute from the drawer.
Threads a #6 drill can tap
Threads from the tap tables on this site that this drill can tap, with the thread percentage it leaves (55–85 % shown).
| Thread | Standard drill | Thread with this drill | Suits |
|---|---|---|---|
| 1/4-20 UNC | #7 | 71 % | Good in steel |
| M6 × 0.75 | 5.2 mm | 84 % | Soft metals, plastics |
| M6 × 1 | 5 mm | 63 % | Hard, tough metals |
Clearance for screws and bolts
Bolts and screws a #6 hole clears, with the diametral clearance and the gap each side. Metric sizes are compared with ISO 273.
| Fastener | Diameter | Clearance | Per side | ISO 273, metric only |
|---|---|---|---|---|
| #8 screw | 0.1640" | 0.0400" | 0.0200" | – |
| #10 screw | 0.1900" | 0.0140" | 0.0070" | – |
| M5 bolt | 5 mm | 0.18 mm | 0.09 mm | Tighter than close fit (5.3 mm) |
Inch clearance is the drill size minus the basic major diameter. A drilled hole usually cuts slightly oversize.
Number drill index
Every size in the series, holes drawn to scale.
Common questions
What size is a #6 drill?
A #6 drill is 0.2040 in, which is 5.18 mm (5.1816 mm exactly).
What is the metric equivalent of a #6 drill?
The nearest metric drill is 5.2 mm, 0.018 mm larger. The other close size is 5.1 mm.
What thread can I tap with a #6 drill?
It leaves about 71 % thread in 1/4-20 UNC and 84 % in M6 × 0.75.
Which fractional drill is closest to #6?
13/64 in (0.2031 in) is the closest, 0.0009 in smaller.
What does a #6 drill clear?
It clears a M5 bolt with 0.18 mm total clearance (0.09 mm per side); for metric bolts: tighter than close fit.