11/32" drill bit size
0.3438 in
8.73 mm · fractional drill
| Inches | 0.3438 in |
| Millimetres | 8.73 mm |
| Nearest metric drill | 8.7 mm |
| System | Fractional (64ths) |
What 11/32" means
11/32" 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 11/32":
| System | Nearest size | Difference |
|---|---|---|
| number | #1 — 0.228 in | 0.1158 in smaller |
| letter | S — 0.348 in | 0.0042 in larger |
| metric | 8.7 mm | 0.031 mm smaller |
The closest substitute is 0.0042 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 0.3438 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 |
|---|---|---|
| 21/64" | 0.3281 in | 8.33 mm |
| Q | 0.332 in | 8.43 mm |
| R | 0.339 in | 8.61 mm |
| 11/32" | 0.3438 in | 8.73 mm |
| S | 0.348 in | 8.84 mm |
| T | 0.358 in | 9.09 mm |
| 23/64" | 0.3594 in | 9.13 mm |
Frequently asked questions
What size is a 11/32" drill bit?
0.3438 inches, which is 8.73 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 11/32" drill bit in mm?
8.73 mm. A metric index will offer 8.7 mm as the nearest stocked size, which is 0.031 mm smaller — enough to matter when tapping and not enough to matter for a clearance hole.
Is 11/32" a tapping drill size?
Not for any of the unified threads on this site. It sits between the sizes the standard taps call for, so it is a clearance or pilot drill rather than a tapping one.
What is the next size up from 11/32"?
S at 0.348 inches — 0.0042 inches larger. Below it is R at 0.339.
Other sizes
- S drill bit — 0.348 in, 8.84 mm
- T drill bit — 0.358 in, 9.09 mm
- 23/64" drill bit — 0.3594 in, 9.13 mm
- U drill bit — 0.368 in, 9.35 mm
- 3/8" drill bit — 0.375 in, 9.52 mm
- V drill bit — 0.377 in, 9.58 mm
- W drill bit — 0.386 in, 9.8 mm
- 25/64" drill bit — 0.3906 in, 9.92 mm