#48 drill size
A #48 number (wire-gauge) drill is 0.0760 in (1.930 mm). It is the cut tap, 50% thread drill for 2-64.
- Decimal inch
- 0.0760
- Millimeters
- 1.930
- Nearest 1/64
- 5/64" (-0.0021)
- Type
- number (wire-gauge) drill
Nearest equivalents in other systems
| System | Drill | Inch | mm | Difference |
|---|---|---|---|---|
| Fractional | 5/64" | 0.0781 | 1.984 | +0.0021 in |
| Metric | 1.95 mm | 0.0768 | 1.950 | +0.0008 in |
Speeds and feeds: in mild steel an HSS drill starts at about 4,520 RPM and 0.0018 in/rev (8.14 IPM); in 6061 aluminum about 12,560 RPM.
#48 drill speeds and feeds by material
Jobber-length twist drill, D = 0.0760 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 | 12,560 | 600 | 30,160 | 0.0017 | 21.4 | 51.3 |
| Brass / free-machining | 150 | 7,540 | 400 | 20,100 | 0.0015 | 11.3 | 30.1 |
| Low-carbon steel (1018) | 90 | 4,520 | 300 | 15,080 | 0.0018 | 8.14 | 27.1 |
| Alloy steel (4140, annealed) | 70 | 3,520 | 250 | 12,560 | 0.0018 | 6.34 | 22.6 |
| Stainless 304 | 40 | 2,010 | 150 | 7,540 | 0.0012 | 2.41 | 9.05 |
| Gray cast iron | 80 | 4,020 | 250 | 12,560 | 0.0011 | 4.42 | 13.8 |
| Titanium 6Al-4V | 25 | 1,260 | 100 | 5,030 | 0.0009 | 1.13 | 4.53 |
| Plastics (acetal) | 300 | 15,080 | 500 | 25,130 | 0.0030 | 45.2 | 75.4 |
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, 4,520 RPM × 0.046 mm/rev = 207 mm/min.
Worked example: #48 drill in 1018 steel
- HSS drill in low-carbon steel: 90 SFM.
- RPM = 3.82 × 90 ÷ 0.0760 ≈ 4,520 RPM.
- Feed for a 0.076 in drill in mild steel ≈ 0.0018 in/rev.
- IPM = 4,520 × 0.0018 = 8.14 IPM.
Peck cycle by hole depth
| Depth | Cycle | Peck | Note |
|---|---|---|---|
| 3×D = 0.228 in (5.8 mm) | G81 (no peck) | None | Up to 3×D a sharp drill clears chips on its own. |
| 5×D = 0.380 in (9.7 mm) | G73 chip-break | 1 × D | Chip-break pecks; full retract if chips pack (soft aluminum, stainless). |
| 8×D = 0.608 in (15.4 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 #48 drill
- 2-64 — cut tap, 50% thread · tap speeds and feeds
Nearest drills
- 1.95 mm: 0.0768 in / 1.950 mm (+0.0008 in)
- 1.9 mm: 0.0748 in / 1.900 mm (-0.0012 in)
- 5/64": 0.0781 in / 1.984 mm (+0.0021 in)
- #47: 0.0785 in / 1.994 mm (+0.0025 in)
Common questions
- What is a #48 drill in decimal and mm?
- 0.0760 in, or 1.930 mm; nearest fractional drill: 5/64" (0.0781 in, +0.0021 in); nearest metric drill: 1.95 mm (0.0768 in, +0.0008 in).
- What RPM for a #48 drill in steel?
- In low-carbon steel (1018) an HSS #48 drill (0.0760 in) runs about 4,520 RPM at 90 SFM; a carbide drill about 15,080 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
- What feed for a #48 drill?
- About 0.0018 in/rev in mild steel, 0.0017 in/rev in aluminum and 0.0012 in/rev in 304 stainless. At 4,520 RPM that is 8.14 IPM in steel (IPM = RPM × IPR).
- What RPM for a #48 drill in aluminum?
- 12,560 RPM with HSS (250 SFM) or up to 30,160 RPM with carbide (600 SFM), feeding about 0.0017 in/rev.
- What tap uses a #48 drill?
- 2-64 (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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