#29 drill size
A #29 drill is 0.1360 in (3.45 mm). It is the standard tap drill for #8-32 UNC and #8-36 UNF; the nearest metric drill is 3.5 mm.
#29 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 |
|---|---|---|---|---|
| 3.4 mm | 0.1339" | −0.054 mm | −0.0021" | Smaller |
| 3.5 mm | 0.1378" | +0.046 mm | +0.0018" | 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 #29 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 #29 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 |
|---|---|---|---|---|
| #2 screw | 0.0860" | 0.0500" | 0.0250" | – |
| #3 screw | 0.0990" | 0.0370" | 0.0185" | – |
| #4 screw | 0.1120" | 0.0240" | 0.0120" | – |
| M3 bolt | 3 mm | 0.45 mm | 0.23 mm | Normal fit (normal 3.4, loose 3.6 mm) |
| #5 screw | 0.1250" | 0.0110" | 0.0055" | – |
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 #29 drill?
A #29 drill is 0.1360 in, which is 3.45 mm (3.4544 mm exactly).
What is the metric equivalent of a #29 drill?
The nearest metric drill is 3.5 mm, 0.046 mm larger. The other close size is 3.4 mm.
What tap uses a #29 drill?
A #29 drill is the standard tap drill for #8-32 UNC (about 69 % thread) and #8-36 UNF (about 78 % thread).
Which fractional drill is closest to #29?
9/64 in (0.1406 in) is the closest, 0.0046 in larger.
What does a #29 drill clear?
It clears a #5 screw with 0.0110" total clearance (0.0055" per side).