10.5 mm drill size
A 10.5 mm metric drill is 0.4134 in (10.500 mm). It is the cut tap, 75% thread drill for M12x1.5.
- Decimal inch
- 0.4134
- Millimeters
- 10.500
- Nearest 1/64
- 13/32" (+0.0071)
- Type
- metric drill
Nearest equivalents in other systems
Speeds and feeds: in mild steel an HSS drill starts at about 830 RPM and 0.0098 in/rev (8.13 IPM); in 6061 aluminum about 2,310 RPM.
10.5 mm drill speeds and feeds by material
Jobber-length twist drill, D = 0.4134 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 | 2,310 | 600 | 5,540 | 0.0090 | 20.8 | 49.9 |
| Brass / free-machining | 150 | 1,390 | 400 | 3,700 | 0.0069 | 9.59 | 25.5 |
| Low-carbon steel (1018) | 90 | 830 | 300 | 2,770 | 0.0098 | 8.13 | 27.1 |
| Alloy steel (4140, annealed) | 70 | 650 | 250 | 2,310 | 0.0108 | 7.02 | 24.9 |
| Stainless 304 | 40 | 370 | 150 | 1,390 | 0.0069 | 2.55 | 9.59 |
| Gray cast iron | 80 | 740 | 250 | 2,310 | 0.0071 | 5.25 | 16.4 |
| Titanium 6Al-4V | 25 | 230 | 100 | 920 | 0.0045 | 1.03 | 4.14 |
| Plastics (acetal) | 300 | 2,770 | 500 | 4,620 | 0.0053 | 14.7 | 24.5 |
Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 830 RPM × 0.249 mm/rev = 207 mm/min.
Worked example: 10.5 mm drill in 1018 steel
- HSS drill in low-carbon steel: 90 SFM.
- RPM = 3.82 × 90 ÷ 0.4134 ≈ 830 RPM.
- Feed for a 0.413 in drill in mild steel ≈ 0.0098 in/rev.
- IPM = 830 × 0.0098 = 8.13 IPM.
Peck cycle by hole depth
| Depth | Cycle | Peck | Note |
|---|---|---|---|
| 3×D = 1.240 in (31.5 mm) | G81 (no peck) | None | Up to 3×D a sharp drill clears chips on its own. |
| 5×D = 2.067 in (52.5 mm) | G73 chip-break | 1 × D | Chip-break pecks; full retract if chips pack (soft aluminum, stainless). |
| 8×D = 3.307 in (84 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 10.5 mm drill
- M12x1.5 — cut tap, 75% thread
Nearest drills
- Letter Z: 0.4130 in / 10.490 mm (-0.0004 in)
- 10.6 mm: 0.4173 in / 10.600 mm (+0.0039 in)
- 10.4 mm: 0.4094 in / 10.400 mm (-0.0039 in)
- 13/32": 0.4063 in / 10.319 mm (-0.0071 in)
Common questions
- What is a 10.5 mm drill in decimal and mm?
- 0.4134 in, or 10.500 mm; nearest fractional drill: 13/32" (0.4063 in, -0.0071 in); nearest number / letter drill: Letter Z (0.4130 in, -0.0004 in).
- What RPM for a 10.5 mm drill in steel?
- In low-carbon steel (1018) an HSS 10.5 mm drill (0.4134 in) runs about 830 RPM at 90 SFM; a carbide drill about 2,770 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
- What feed for a 10.5 mm drill?
- About 0.0098 in/rev in mild steel, 0.0090 in/rev in aluminum and 0.0069 in/rev in 304 stainless. At 830 RPM that is 8.13 IPM in steel (IPM = RPM × IPR).
- What RPM for a 10.5 mm drill in aluminum?
- 2,310 RPM with HSS (250 SFM) or up to 5,540 RPM with carbide (600 SFM), feeding about 0.0090 in/rev.
- What tap uses a 10.5 mm drill?
- M12x1.5 (cut tap, 75% 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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