Letter L drill size
A letter L drill is 0.2900 in (7.37 mm). It sits between letter K and letter M in the letter series; the nearest metric drill is 7.4 mm.
Letter L 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 |
|---|---|---|---|---|
| 7.3 mm | 0.2874" | −0.066 mm | −0.0026" | Smaller |
| 7.4 mm | 0.2913" | +0.034 mm | +0.0013" | Larger |
Nearby inch drills
The next size down and up in each inch series, so you can pick a substitute from the drawer.
| Drill | Series | Inch | mm | Difference |
|---|---|---|---|---|
| #1 | Number | 0.2280" | 5.79 mm | −0.0620" |
| Letter K | Letter | 0.2810" | 7.14 mm | −0.0090" |
| 9/32" | Fractional | 0.2812" | 7.14 mm | −0.0087" |
| Letter L | Letter | 0.2900" | 7.37 mm | this size |
| Letter M | Letter | 0.2950" | 7.49 mm | +0.0050" |
| 19/64" | Fractional | 0.2969" | 7.54 mm | +0.0069" |
Threads a Letter L drill can tap
No thread in the tap tables on this site falls between 55 and 85 % thread with this drill, so it is not a useful tap drill for them. Drills this size are mostly used for clearance, pilot and pin holes.
Clearance for screws and bolts
Bolts and screws a Letter L 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 |
|---|---|---|---|---|
| 1/4" bolt | 0.2500" | 0.0400" | 0.0200" | – |
Inch clearance is the drill size minus the basic major diameter. A drilled hole usually cuts slightly oversize.
Letter drill index
Every size in the series, holes drawn to scale.
Common questions
What size is a letter L drill?
A letter L drill is 0.2900 in, which is 7.37 mm (7.3660 mm exactly).
What is the metric equivalent of a letter L drill?
The nearest metric drill is 7.4 mm, 0.034 mm larger. The other close size is 7.3 mm.
Which fractional drill is closest to letter L?
19/64 in (0.2969 in) is the closest, 0.0069 in larger.
What does a letter L drill clear?
It clears a 1/4" bolt with 0.0400" total clearance (0.0200" per side).