A #56 drill measures 0.0465 inch (1.181 mm). The closest fractional drill is 3/64" (0.0469") and the closest metric drill is 1.2 mm (0.0472").
What are the #56 drill equivalents?
| Drill | System | Decimal (in) | mm | Difference (in) |
|---|---|---|---|---|
| #56 | number | 0.0465 | 1.181 | 0 |
| 3/64" | fraction | 0.0469 | 1.191 | +0.0004 |
| 1.2 mm | metric | 0.0472 | 1.200 | +0.0007 |
Drill sets that include this size
Number and letter sizes come in indexed sets; buy the set rather than single drills.
What speed should a #56 drill run?
| Material | RPM (HSS) | Feed (in/rev) |
|---|---|---|
| 6061-T6 aluminum | 16,429 | 0.0009 |
| 360 free-machining brass | 12,322 | 0.0008 |
| 1018 cold rolled steel | 6,572 | 0.0007 |
| 304 stainless steel | 3,286 | 0.0005 |
Starting points from conservative HSS drilling speeds. Small drills often call for more RPM than a benchtop drill press offers; run at the top speed and feed gently. Use cutting oil in steel and stainless, and clamp the work: never hold it by hand.
Cutting fluid for drilling
Frequently asked questions
What is a #56 drill in inches?
0.0465 inch, which is 1.181 mm. Number drills get smaller as the number rises, so the next number up is a smaller drill. If you do not have this exact size, 1.2 mm is within 0.0007 inch.
What tap uses a #56 drill?
No common UNC or UNF thread uses it as its standard 75% tap drill, but it often serves as an alternative drill for a slightly different percentage of thread, or as a clearance or pilot size. The tap drill chart lists every standard pairing.