#16 drill size
A #16 number (wire-gauge) drill is 0.1770 in (4.496 mm). It is the cut tap, 75% thread drill for 12-24.
- Decimal inch
- 0.1770
- Millimeters
- 4.496
- Nearest 1/64
- 11/64" (+0.0051)
- Type
- number (wire-gauge) drill
Nearest equivalents in other systems
Speeds and feeds: in mild steel an HSS drill starts at about 1,940 RPM and 0.0044 in/rev (8.54 IPM); in 6061 aluminum about 5,400 RPM.
#16 drill speeds and feeds by material
Jobber-length twist drill, D = 0.1770 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.
| Material | HSS SFM | HSS RPM | Carbide SFM | Carbide RPM | Feed (in/rev) | HSS IPM | Carbide IPM |
|---|---|---|---|---|---|---|---|
| Aluminum (6061) | 250 | 5,400 | 600 | 12,950 | 0.0042 | 22.7 | 54.4 |
| Brass / free-machining | 150 | 3,240 | 400 | 8,630 | 0.0036 | 11.7 | 31.1 |
| Low-carbon steel (1018) | 90 | 1,940 | 300 | 6,470 | 0.0044 | 8.54 | 28.5 |
| Alloy steel (4140, annealed) | 70 | 1,510 | 250 | 5,400 | 0.0044 | 6.64 | 23.8 |
| Stainless 304 | 40 | 860 | 150 | 3,240 | 0.0029 | 2.49 | 9.40 |
| Gray cast iron | 80 | 1,730 | 250 | 5,400 | 0.0029 | 5.02 | 15.7 |
| Titanium 6Al-4V | 25 | 540 | 100 | 2,160 | 0.0022 | 1.19 | 4.75 |
| Plastics (acetal) | 300 | 6,470 | 500 | 10,790 | 0.0046 | 29.8 | 49.6 |
Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 1,940 RPM × 0.112 mm/rev = 217 mm/min.
Worked example: #16 drill in 1018 steel
- HSS drill in low-carbon steel: 90 SFM.
- RPM = 3.82 × 90 ÷ 0.1770 ≈ 1,940 RPM.
- Feed for a 0.177 in drill in mild steel ≈ 0.0044 in/rev.
- IPM = 1,940 × 0.0044 = 8.54 IPM.
Peck cycle by hole depth
| Depth | Cycle | Peck | Note |
|---|---|---|---|
| 3×D = 0.531 in (13.5 mm) | G81 (no peck) | None | Up to 3×D a sharp drill clears chips on its own. |
| 5×D = 0.885 in (22.5 mm) | G73 chip-break | 1 × D | Chip-break pecks; full retract if chips pack (soft aluminum, stainless). |
| 8×D = 1.416 in (36 mm) | G83 full retract | 0.5-1 × D, shrinking with depth | Retract to clear chips; reduce feed ~10-20% past 5×D. |
Taps that use a #16 drill
- 12-24 — cut tap, 75% thread · tap speeds and feeds
- 10-32 — form (roll) tap, 65% thread · tap speeds and feeds
Nearest drills
- 4.5 mm: 0.1772 in / 4.500 mm (+0.0002 in)
- #15: 0.1800 in / 4.572 mm (+0.0030 in)
- 4.4 mm: 0.1732 in / 4.400 mm (-0.0038 in)
- #17: 0.1730 in / 4.394 mm (-0.0040 in)
Common questions
- What is a #16 drill in decimal and mm?
- 0.1770 in, or 4.496 mm; nearest fractional drill: 11/64" (0.1719 in, -0.0051 in); nearest metric drill: 4.5 mm (0.1772 in, +0.0002 in).
- What RPM for a #16 drill in steel?
- In low-carbon steel (1018) an HSS #16 drill (0.1770 in) runs about 1,940 RPM at 90 SFM; a carbide drill about 6,470 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
- What feed for a #16 drill?
- About 0.0044 in/rev in mild steel, 0.0042 in/rev in aluminum and 0.0029 in/rev in 304 stainless. At 1,940 RPM that is 8.54 IPM in steel (IPM = RPM × IPR).
- What RPM for a #16 drill in aluminum?
- 5,400 RPM with HSS (250 SFM) or up to 12,950 RPM with carbide (600 SFM), feeding about 0.0042 in/rev.
- What tap uses a #16 drill?
- 12-24 (cut tap, 75% thread); 10-32 (form (roll) tap, 65% thread).
Nearby drill sizes
Sources
- Machinery's Handbook, 31st ed., Speeds and Feeds for Drilling, Reaming and Threading (Tables 17-23) — HSS and carbide drilling SFM (rounded).
- RedLine Tools (Productivity Inc.) catalog p. 340, Cobalt & HSS Drills Speeds & Feeds — feed per rev by drill diameter and material (middle of the catalog range).
- ASME B94.11M twist drills: number (#1-#80) and letter (A-Z) drill sizes; drill size reference.
Material feed multipliers (aluminum 1.3×, brass 1.1×, 4140 0.85×, stainless and titanium 0.7× the mild-steel feed) are JobLine estimates. Peck guidance is JobLine shop practice. Use your drill maker's data first.
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