#33 drill size
A #33 drill is 0.1130 in (2.87 mm). It is the standard tap drill for #6-40 UNF; the nearest metric drill is 2.85 mm.
#33 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 |
|---|---|---|---|---|
| 2.85 mm | 0.1122" | −0.020 mm | −0.0008" | Smaller |
| 2.9 mm | 0.1142" | +0.030 mm | +0.0012" | 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 #33 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 |
|---|---|---|---|
| #6-40 UNF | #33 | 77 % | Standard drill |
| M3.5 × 0.6 | 2.9 mm | 81 % | Soft metals, plastics |
| #6-32 UNC | #36 | 62 % | Hard, tough metals |
Clearance for screws and bolts
Bolts and screws a #33 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 |
|---|---|---|---|---|
| #1 screw | 0.0730" | 0.0400" | 0.0200" | – |
| #2 screw | 0.0860" | 0.0270" | 0.0135" | – |
| M2.5 bolt | 2.5 mm | 0.37 mm | 0.19 mm | Close fit (close 2.7, normal 2.9 mm) |
| #3 screw | 0.0990" | 0.0140" | 0.0070" | – |
| #4 screw | 0.1120" | 0.0010" | 0.0005" | – |
Inch clearance is the drill size minus the basic major diameter. A drilled hole usually cuts slightly oversize.
Number drill index
Every size in the series, holes drawn to scale.
Common questions
What size is a #33 drill?
A #33 drill is 0.1130 in, which is 2.87 mm (2.8702 mm exactly).
What is the metric equivalent of a #33 drill?
The nearest metric drill is 2.85 mm, 0.020 mm smaller. The other close size is 2.9 mm.
What tap uses a #33 drill?
A #33 drill is the standard tap drill for #6-40 UNF (about 77 % thread).
Which fractional drill is closest to #33?
7/64 in (0.1094 in) is the closest, 0.0036 in smaller.
What does a #33 drill clear?
It clears a #4 screw with 0.0010" total clearance (0.0005" per side).