53/64" drill size
A 53/64 in drill is 0.8281 in (21.03 mm). It sits between 13/16 in and 27/32 in in the fractional series; the nearest metric drill is 21.0 mm.
53/64" 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 |
|---|---|---|---|---|
| 21.0 mm | 0.8268" | −0.034 mm | −0.0014" | Smaller |
| 21.1 mm | 0.8307" | +0.066 mm | +0.0026" | 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 53/64" 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 |
|---|---|---|---|
| M24 × 3 | 21 mm | 76 % | Soft metals, plastics |
Clearance for screws and bolts
Bolts and screws a 53/64" 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 |
|---|---|---|---|---|
| M20 bolt | 20 mm | 1.03 mm | 0.52 mm | Close fit (close 21, normal 22 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 53/64 in drill?
A 53/64 in drill is 0.8281 in, which is 21.03 mm (21.0344 mm exactly).
What is the metric equivalent of a 53/64 in drill?
The nearest metric drill is 21.0 mm, 0.034 mm smaller. The other close size is 21.1 mm.
What thread can I tap with a 53/64 in drill?
It leaves about 76 % thread in M24 × 3.
What does a 53/64 in drill clear?
It clears a M20 bolt with 1.03 mm total clearance (0.52 mm per side); for metric bolts: close fit.