#64 drill size
A #64 number (wire-gauge) drill is 0.0360 in (0.914 mm).
- Decimal inch
- 0.0360
- Millimeters
- 0.914
- Nearest 1/64
- 1/32" (+0.0047)
- Type
- number (wire-gauge) drill
Nearest equivalents in other systems
| System | Drill | Inch | mm | Difference |
|---|---|---|---|---|
| Fractional | 1/32" | 0.0313 | 0.794 | -0.0047 in |
| Metric | 0.9 mm | 0.0354 | 0.900 | -0.0006 in |
Speeds and feeds: in mild steel an HSS drill starts at about 9,550 RPM and 0.0008 in/rev (7.64 IPM); in 6061 aluminum about 26,530 RPM.
#64 drill speeds and feeds by material
Jobber-length twist drill, D = 0.0360 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 | 26,530 | 600 | 63,660 | 0.0008 | 21.2 | 50.9 |
| Brass / free-machining | 150 | 15,920 | 400 | 42,440 | 0.0007 | 11.1 | 29.7 |
| Low-carbon steel (1018) | 90 | 9,550 | 300 | 31,830 | 0.0008 | 7.64 | 25.5 |
| Alloy steel (4140, annealed) | 70 | 7,430 | 250 | 26,530 | 0.0008 | 5.94 | 21.2 |
| Stainless 304 | 40 | 4,240 | 150 | 15,920 | 0.0006 | 2.54 | 9.55 |
| Gray cast iron | 80 | 8,490 | 250 | 26,530 | 0.0005 | 4.25 | 13.3 |
| Titanium 6Al-4V | 25 | 2,650 | 100 | 10,610 | 0.0004 | 1.06 | 4.24 |
| Plastics (acetal) | 300 | 31,830 | 500 | 53,050 | 0.0014 | 44.6 | 74.3 |
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, 9,550 RPM × 0.020 mm/rev = 194 mm/min.
Worked example: #64 drill in 1018 steel
- HSS drill in low-carbon steel: 90 SFM.
- RPM = 3.82 × 90 ÷ 0.0360 ≈ 9,550 RPM.
- Feed for a 0.036 in drill in mild steel ≈ 0.0008 in/rev.
- IPM = 9,550 × 0.0008 = 7.64 IPM.
Peck cycle by hole depth
| Depth | Cycle | Peck | Note |
|---|---|---|---|
| 3×D = 0.108 in (2.7 mm) | G81 (no peck) | None | Up to 3×D a sharp drill clears chips on its own. |
| 5×D = 0.180 in (4.6 mm) | G73 chip-break | 1 × D | Chip-break pecks; full retract if chips pack (soft aluminum, stainless). |
| 8×D = 0.288 in (7.3 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 #64 drill
No standard UNC, UNF or metric tap in our tables calls for a #64 drill. Use it for clearance, pilot or reamer prep holes.
Nearest drills
- 0.9 mm: 0.0354 in / 0.900 mm (-0.0006 in)
- #65: 0.0350 in / 0.889 mm (-0.0010 in)
- #63: 0.0370 in / 0.940 mm (+0.0010 in)
- 0.95 mm: 0.0374 in / 0.950 mm (+0.0014 in)
Common questions
- What is a #64 drill in decimal and mm?
- 0.0360 in, or 0.914 mm; nearest fractional drill: 1/32" (0.0313 in, -0.0047 in); nearest metric drill: 0.9 mm (0.0354 in, -0.0006 in).
- What RPM for a #64 drill in steel?
- In low-carbon steel (1018) an HSS #64 drill (0.0360 in) runs about 9,550 RPM at 90 SFM; a carbide drill about 31,830 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
- What feed for a #64 drill?
- About 0.0008 in/rev in mild steel, 0.0008 in/rev in aluminum and 0.0006 in/rev in 304 stainless. At 9,550 RPM that is 7.64 IPM in steel (IPM = RPM × IPR).
- What RPM for a #64 drill in aluminum?
- 26,530 RPM with HSS (250 SFM) or up to 63,660 RPM with carbide (600 SFM), feeding about 0.0008 in/rev.
- What size is a #64 drill?
- 0.0360 in / 0.914 mm. The nearest other drills are 0.9 mm (0.0354 in), #65 (0.0350 in), #63 (0.0370 in).
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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