#44 drill size
A #44 number (wire-gauge) drill is 0.0860 in (2.184 mm). It is the cut tap, 50% thread drill for 3-48.
- Decimal inch
- 0.0860
- Millimeters
- 2.184
- Nearest 1/64
- 3/32" (-0.0078)
- Type
- number (wire-gauge) drill
Nearest equivalents in other systems
Speeds and feeds: in mild steel an HSS drill starts at about 4,000 RPM and 0.0020 in/rev (8.00 IPM); in 6061 aluminum about 11,100 RPM.
#44 drill speeds and feeds by material
Jobber-length twist drill, D = 0.0860 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 | 11,100 | 600 | 26,650 | 0.0020 | 22.2 | 53.3 |
| Brass / free-machining | 150 | 6,660 | 400 | 17,770 | 0.0017 | 11.3 | 30.2 |
| Low-carbon steel (1018) | 90 | 4,000 | 300 | 13,320 | 0.0020 | 8.00 | 26.6 |
| Alloy steel (4140, annealed) | 70 | 3,110 | 250 | 11,100 | 0.0020 | 6.22 | 22.2 |
| Stainless 304 | 40 | 1,780 | 150 | 6,660 | 0.0014 | 2.49 | 9.32 |
| Gray cast iron | 80 | 3,550 | 250 | 11,100 | 0.0012 | 4.26 | 13.3 |
| Titanium 6Al-4V | 25 | 1,110 | 100 | 4,440 | 0.0011 | 1.22 | 4.88 |
| Plastics (acetal) | 300 | 13,320 | 500 | 22,210 | 0.0034 | 45.3 | 75.5 |
Small drills: the computed RPM is above most spindles. Run at your spindle's maximum and keep the feed per rev; feed drops in proportion.
Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 4,000 RPM × 0.051 mm/rev = 203 mm/min.
Worked example: #44 drill in 1018 steel
- HSS drill in low-carbon steel: 90 SFM.
- RPM = 3.82 × 90 ÷ 0.0860 ≈ 4,000 RPM.
- Feed for a 0.086 in drill in mild steel ≈ 0.0020 in/rev.
- IPM = 4,000 × 0.0020 = 8.00 IPM.
Peck cycle by hole depth
| Depth | Cycle | Peck | Note |
|---|---|---|---|
| 3×D = 0.258 in (6.6 mm) | G81 (no peck) | None | Up to 3×D a sharp drill clears chips on its own. |
| 5×D = 0.430 in (10.9 mm) | G73 chip-break | 1 × D | Chip-break pecks; full retract if chips pack (soft aluminum, stainless). |
| 8×D = 0.688 in (17.5 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 #44 drill
- 3-48 — cut tap, 50% thread · tap speeds and feeds
- 3-56 — cut tap, 50% thread · tap speeds and feeds
Nearest drills
- 2.2 mm: 0.0866 in / 2.200 mm (+0.0006 in)
- 2.15 mm: 0.0847 in / 2.150 mm (-0.0014 in)
- 2.25 mm: 0.0886 in / 2.250 mm (+0.0026 in)
- #43: 0.0890 in / 2.261 mm (+0.0030 in)
Common questions
- What is a #44 drill in decimal and mm?
- 0.0860 in, or 2.184 mm; nearest fractional drill: 3/32" (0.0938 in, +0.0077 in); nearest metric drill: 2.2 mm (0.0866 in, +0.0006 in).
- What RPM for a #44 drill in steel?
- In low-carbon steel (1018) an HSS #44 drill (0.0860 in) runs about 4,000 RPM at 90 SFM; a carbide drill about 13,320 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
- What feed for a #44 drill?
- About 0.0020 in/rev in mild steel, 0.0020 in/rev in aluminum and 0.0014 in/rev in 304 stainless. At 4,000 RPM that is 8.00 IPM in steel (IPM = RPM × IPR).
- What RPM for a #44 drill in aluminum?
- 11,100 RPM with HSS (250 SFM) or up to 26,650 RPM with carbide (600 SFM), feeding about 0.0020 in/rev.
- What tap uses a #44 drill?
- 3-48 (cut tap, 50% thread); 3-56 (cut tap, 50% 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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