A #16 drill measures 0.1770 inch (4.496 mm). The closest fractional drill is 11/64" (0.1719") and the closest metric drill is 4.5 mm (0.1772"). It is the standard tap drill for #12-24.
What are the #16 drill equivalents?
| Drill | System | Decimal (in) | mm | Difference (in) |
|---|---|---|---|---|
| #16 | number | 0.1770 | 4.496 | 0 |
| 4.5 mm | metric | 0.1772 | 4.500 | +0.0002 |
Tap drill for: #12-24.
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 #16 drill run?
| Material | RPM (HSS) | Feed (in/rev) |
|---|---|---|
| 6061-T6 aluminum | 4,316 | 0.0035 |
| 360 free-machining brass | 3,237 | 0.0032 |
| 1018 cold rolled steel | 1,726 | 0.0027 |
| 304 stainless steel | 863 | 0.0018 |
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 #16 drill in inches?
0.1770 inch, which is 4.496 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, 4.5 mm is within 0.0002 inch.
What tap uses a #16 drill?
It is the standard 75% thread tap drill for #12-24. Tap drills are chosen to leave about 75% of full thread depth, the balance of strength and tapping torque that published charts use.