15/32" drill bit size
0.4688 in
11.91 mm · fractional drill
| Inches | 0.4688 in |
| Millimetres | 11.91 mm |
| Nearest metric drill | 11.9 mm |
| System | Fractional (64ths) |
What 15/32" means
15/32" 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 15/32":
| System | Nearest size | Difference |
|---|---|---|
| number | #1 — 0.228 in | 0.2408 in smaller |
| letter | Z — 0.413 in | 0.0558 in smaller |
| metric | 11.9 mm | 0.006 mm smaller |
The closest substitute is 0.0558 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 gets drilled at 0.4688 inches
Clearance holes for bolts up to about half an inch, and tapping drills for the larger unified threads. Above a quarter inch a hand drill starts to want two hands and a slower speed, and the bit wants a pilot hole.
Either side of it
| Drill | Inches | Millimetres |
|---|---|---|
| 27/64" | 0.4219 in | 10.72 mm |
| 7/16" | 0.4375 in | 11.11 mm |
| 29/64" | 0.4531 in | 11.51 mm |
| 15/32" | 0.4688 in | 11.91 mm |
| 31/64" | 0.4844 in | 12.3 mm |
| 1/2" | 0.5 in | 12.7 mm |
| 33/64" | 0.5156 in | 13.1 mm |
Frequently asked questions
What size is a 15/32" drill bit?
0.4688 inches, which is 11.91 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 15/32" drill bit in mm?
11.91 mm. A metric index will offer 11.9 mm as the nearest stocked size, which is near enough identical.
Is 15/32" a tapping drill size?
Not for any of the unified threads on this site. The next size up, 31/64", is the tapping drill for 9/16-12.
What is the next size up from 15/32"?
31/64" at 0.4844 inches — 0.0156 inches larger. Below it is 29/64" at 0.4531.
Other sizes
- 31/64" drill bit — 0.4844 in, 12.3 mm
- 1/2" drill bit — 0.5 in, 12.7 mm
- 33/64" drill bit — 0.5156 in, 13.1 mm
- 17/32" drill bit — 0.5313 in, 13.49 mm
- 35/64" drill bit — 0.5469 in, 13.89 mm
- 9/16" drill bit — 0.5625 in, 14.29 mm
- 37/64" drill bit — 0.5781 in, 14.68 mm
- 19/32" drill bit — 0.5938 in, 15.08 mm