19.5 mm drill size
A 19.5 mm metric drill is 0.7677 in (19.500 mm). It is the cut tap, 75% thread drill for M22x2.5.
- Decimal inch
- 0.7677
- Millimeters
- 19.500
- Nearest 1/64
- 49/64" (+0.0021)
- Type
- metric drill
Nearest equivalents in other systems
Speeds and feeds: in mild steel an HSS drill starts at about 450 RPM and 0.0116 in/rev (5.22 IPM); in 6061 aluminum about 1,240 RPM.
19.5 mm drill speeds and feeds by material
Jobber-length twist drill, D = 0.7677 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 | 1,240 | 600 | 2,990 | 0.0111 | 13.8 | 33.2 |
| Brass / free-machining | 150 | 750 | 400 | 1,990 | 0.0091 | 6.83 | 18.1 |
| Low-carbon steel (1018) | 90 | 450 | 300 | 1,490 | 0.0116 | 5.22 | 17.3 |
| Alloy steel (4140, annealed) | 70 | 350 | 250 | 1,240 | 0.0121 | 4.23 | 15.0 |
| Stainless 304 | 40 | 200 | 150 | 750 | 0.0096 | 1.92 | 7.20 |
| Gray cast iron | 80 | 400 | 250 | 1,240 | 0.0101 | 4.04 | 12.5 |
| Titanium 6Al-4V | 25 | 120 | 100 | 500 | 0.0055 | 0.66 | 2.75 |
| Plastics (acetal) | 300 | 1,490 | 500 | 2,490 | 0.0071 | 10.6 | 17.7 |
Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 450 RPM × 0.295 mm/rev = 133 mm/min.
Worked example: 19.5 mm drill in 1018 steel
- HSS drill in low-carbon steel: 90 SFM.
- RPM = 3.82 × 90 ÷ 0.7677 ≈ 450 RPM.
- Feed for a 0.768 in drill in mild steel ≈ 0.0116 in/rev.
- IPM = 450 × 0.0116 = 5.22 IPM.
Peck cycle by hole depth
| Depth | Cycle | Peck | Note |
|---|---|---|---|
| 3×D = 2.303 in (58.5 mm) | G81 (no peck) | None | Up to 3×D a sharp drill clears chips on its own. |
| 5×D = 3.839 in (97.5 mm) | G73 chip-break | 1 × D | Chip-break pecks; full retract if chips pack (soft aluminum, stainless). |
| 8×D = 6.142 in (156 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 19.5 mm drill
- M22x2.5 — cut tap, 75% thread · tap speeds and feeds
Nearest drills
- 49/64": 0.7656 in / 19.447 mm (-0.0021 in)
- 19.75 mm: 0.7776 in / 19.750 mm (+0.0098 in)
- 19.25 mm: 0.7579 in / 19.250 mm (-0.0098 in)
- 25/32": 0.7813 in / 19.844 mm (+0.0135 in)
Common questions
- What is a 19.5 mm drill in decimal and mm?
- 0.7677 in, or 19.500 mm; nearest fractional drill: 49/64" (0.7656 in, -0.0021 in); nearest number / letter drill: Letter Z (0.4130 in, -0.3547 in).
- What RPM for a 19.5 mm drill in steel?
- In low-carbon steel (1018) an HSS 19.5 mm drill (0.7677 in) runs about 450 RPM at 90 SFM; a carbide drill about 1,490 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
- What feed for a 19.5 mm drill?
- About 0.0116 in/rev in mild steel, 0.0111 in/rev in aluminum and 0.0096 in/rev in 304 stainless. At 450 RPM that is 5.22 IPM in steel (IPM = RPM × IPR).
- What RPM for a 19.5 mm drill in aluminum?
- 1,240 RPM with HSS (250 SFM) or up to 2,990 RPM with carbide (600 SFM), feeding about 0.0111 in/rev.
- What tap uses a 19.5 mm drill?
- M22x2.5 (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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