59/64" drill bit size
0.9219 in
23.42 mm · fractional drill · tapping drill for 1-12
| Inches | 0.9219 in |
| Millimetres | 23.42 mm |
| Nearest metric drill | 23.4 mm |
| System | Fractional (64ths) |
| Taps | 1-12 |
What 59/64" means
59/64" is a fractional drill, stepping in 64ths of an inch. Fractional sizes are the coarsest of the three systems, which is why a fractional set alone cannot hit most tapping sizes and why number and letter drills exist at all.
The same hole in the other systems
Three drill systems overlap across this range and a workshop rarely has all three. The nearest bit of each other kind to 59/64":
| System | Nearest size | Difference |
|---|---|---|
| number | #1 — 0.228 in | 0.6939 in smaller |
| letter | Z — 0.413 in | 0.5089 in smaller |
| metric | 23.4 mm | 0.016 mm smaller |
The closest substitute is 0.5089 inches away. For a clearance hole that is nothing; for a tapping hole it moves the thread engagement by several per cent, which is the difference between an easy tap and a broken one.
What 59/64" is for
59/64" is the standard tapping drill for 1-12 at 75% thread engagement. That is not a coincidence of the tables: the theoretical figure for 1-12 works out at 0.9188 inches, and 59/64" at 0.9219 is the nearest drill that exists.
What gets drilled at 0.9219 inches
Half an inch and up is where twist drills stop being the obvious tool. A bit this size in mild steel needs a pilot, a slow speed and something to hold the work; past three-quarters of an inch most people reach for a hole saw or a step drill instead.
Either side of it
| Drill | Inches | Millimetres |
|---|---|---|
| 7/8" | 0.875 in | 22.23 mm |
| 57/64" | 0.8906 in | 22.62 mm |
| 29/32" | 0.9063 in | 23.02 mm |
| 59/64" | 0.9219 in | 23.42 mm |
| 15/16" | 0.9375 in | 23.81 mm |
| 61/64" | 0.9531 in | 24.21 mm |
| 31/32" | 0.9688 in | 24.61 mm |
Frequently asked questions
What size is a 59/64" drill bit?
0.9219 inches, which is 23.42 mm. Fractional drills step in 64ths of an inch, which is the coarsest of the three systems and the one most home sets contain.
What is a 59/64" drill bit in mm?
23.42 mm. A metric index will offer 23.4 mm as the nearest stocked size, which is near enough identical.
What tap does a 59/64" drill bit go with?
1-12 at the standard 75% thread. That thread comes out at a theoretical diameter this drill is the nearest stocked size to.
What is the next size up from 59/64"?
15/16" at 0.9375 inches — 0.0156 inches larger. Below it is 29/32" at 0.9063.
Other sizes
- 15/16" drill bit — 0.9375 in, 23.81 mm
- 61/64" drill bit — 0.9531 in, 24.21 mm
- 31/32" drill bit — 0.9688 in, 24.61 mm
- 63/64" drill bit — 0.9844 in, 25 mm
- 1/1" drill bit — 1 in, 25.4 mm
- 1/64" drill bit — 0.0156 in, 0.4 mm
- 1/32" drill bit — 0.0313 in, 0.79 mm
- #60 drill bit — 0.04 in, 1.02 mm