11/16" drill size
A 11/16 in drill is 0.6875 in (17.46 mm). It is the standard tap drill for 3/4-16 UNF; the nearest metric drill is 17.5 mm.
11/16" at a glance
Decimal, metric and the nearest sizes in the other series.
- Decimal inch
- 0.6875"
- Millimetres
- 17.46 mm 17.4625
- Nearest metric drill
- 17.5 mm +0.038 mm
- Hole area
- 0.371 in² 239.5 mm²
- Tap drill for
- 3/4-16 UNF
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 |
|---|---|---|---|---|
| 17.4 mm | 0.6850" | −0.062 mm | −0.0025" | Smaller |
| 17.5 mm | 0.6890" | +0.038 mm | +0.0015" | 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 11/16" 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 |
|---|---|---|---|
| 3/4-16 UNF | 11/16 | 77 % | Standard drill |
| M20 × 2.5 | 17.5 mm | 78 % | Soft metals, plastics |
Clearance for screws and bolts
Bolts and screws a 11/16" 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 |
|---|---|---|---|---|
| 5/8" bolt | 0.6250" | 0.0625" | 0.0312" | – |
| M16 bolt | 16 mm | 1.46 mm | 0.73 mm | Close fit (close 17, normal 17.5 mm) |
Inch clearance is the drill size minus the basic major diameter. A drilled hole usually cuts slightly oversize.
Fractional drill index
Every size in the series, holes drawn to scale.
Common questions
What size is a 11/16 in drill?
A 11/16 in drill is 0.6875 in, which is 17.46 mm (17.4625 mm exactly).
What is the metric equivalent of a 11/16 in drill?
The nearest metric drill is 17.5 mm, 0.038 mm larger. The other close size is 17.4 mm.
What tap uses a 11/16 in drill?
A 11/16 in drill is the standard tap drill for 3/4-16 UNF (about 77 % thread).
What does a 11/16 in drill clear?
It clears a M16 bolt with 1.46 mm total clearance (0.73 mm per side); for metric bolts: close fit.