#44 drill size
A #44 drill is 0.0860 in (2.18 mm). It sits between #45 and #43 in the number series; the nearest metric drill is 2.2 mm.
#44 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 |
|---|---|---|---|---|
| 2.15 mm | 0.0846" | −0.034 mm | −0.0014" | Smaller |
| 2.2 mm | 0.0866" | +0.016 mm | +0.0006" | 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 #44 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).
Clearance for screws and bolts
Bolts and screws a #44 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" | 0.0130" | 0.0065" | – |
| M2 bolt | 2 mm | 0.18 mm | 0.09 mm | Tighter than close fit (2.2 mm) |
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 #44 drill?
A #44 drill is 0.0860 in, which is 2.18 mm (2.1844 mm exactly).
What is the metric equivalent of a #44 drill?
The nearest metric drill is 2.2 mm, 0.016 mm larger. The other close size is 2.15 mm.
What thread can I tap with a #44 drill?
It leaves about 80 % thread in #4-40 UNC and 56 % in #3-56 UNF.
Which fractional drill is closest to #44?
3/32 in (0.0938 in) is the closest, 0.0078 in larger.
What does a #44 drill clear?
It clears a M2 bolt with 0.18 mm total clearance (0.09 mm per side); for metric bolts: tighter than close fit.