7/64" drill bit size
0.1094 in
2.78 mm · fractional drill
| Inches | 0.1094 in |
| Millimetres | 2.78 mm |
| Nearest metric drill | 2.8 mm |
| System | Fractional (64ths) |
What 7/64" means
7/64" 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 7/64":
| System | Nearest size | Difference |
|---|---|---|
| number | #35 — 0.11 in | 0.0006 in larger |
| letter | A — 0.234 in | 0.1246 in larger |
| metric | 2.8 mm | 0.022 mm larger |
One of those is within three thousandths of an inch, which is inside the tolerance of most hand-held work — substitute it and nobody will know.
What gets drilled at 0.1094 inches
The busiest part of the number series. Tapping drills for machine screws from #4 to #12 sit in here, along with pilot holes for wood screws and clearance for small pins. If a number drill in a workshop is worn out, it is usually one of these.
Either side of it
| Drill | Inches | Millimetres |
|---|---|---|
| #38 | 0.1015 in | 2.58 mm |
| #37 | 0.104 in | 2.64 mm |
| #36 | 0.1065 in | 2.71 mm |
| 7/64" | 0.1094 in | 2.78 mm |
| #35 | 0.11 in | 2.79 mm |
| #34 | 0.111 in | 2.82 mm |
| #33 | 0.113 in | 2.87 mm |
Frequently asked questions
What size is a 7/64" drill bit?
0.1094 inches, which is 2.78 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 7/64" drill bit in mm?
2.78 mm. A metric index will offer 2.8 mm as the nearest stocked size, which is 0.022 mm larger — enough to matter when tapping and not enough to matter for a clearance hole.
Is 7/64" 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 7/64"?
#35 at 0.11 inches — 0.0006 inches larger. Below it is #36 at 0.1065.
Other sizes
- #35 drill bit — 0.11 in, 2.79 mm
- #34 drill bit — 0.111 in, 2.82 mm
- #33 drill bit — 0.113 in, 2.87 mm
- #32 drill bit — 0.116 in, 2.95 mm
- #31 drill bit — 0.12 in, 3.05 mm
- 1/8" drill bit — 0.125 in, 3.18 mm
- #30 drill bit — 0.1285 in, 3.26 mm
- #29 drill bit — 0.136 in, 3.45 mm