What is a 3/4" drill in decimal and mm?

0.7500 in, or 19.050 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.3370 in); nearest metric drill: 19.0 mm (0.7480 in, -0.0020 in).

What RPM for a 3/4" drill in steel?

In low-carbon steel (1018) an HSS 3/4" drill (0.7500 in) runs about 460 RPM at 90 SFM; a carbide drill about 1,530 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 3/4" drill?

About 0.0115 in/rev in mild steel, 0.0110 in/rev in aluminum and 0.0095 in/rev in 304 stainless. At 460 RPM that is 5.29 IPM in steel (IPM = RPM × IPR).

What RPM for a 3/4" drill in aluminum?

1,270 RPM with HSS (250 SFM) or up to 3,060 RPM with carbide (600 SFM), feeding about 0.0110 in/rev.

What size is a 3/4" drill?

0.7500 in / 19.05 mm. The nearest other drills are 19.0 mm (0.7480 in), 19.25 mm (0.7579 in), 18.75 mm (0.7382 in).

3/4" drill size

A 3/4" fractional drill is 0.7500 in (19.050 mm).

Decimal inch: 0.7500
Millimeters: 19.050
Nearest 1/64: 3/4" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 3/4"
System	Drill	Inch	mm	Difference
Number / letter	Letter Z	0.4130	10.490	-0.3370 in
Metric	19.0 mm	0.7480	19.000	-0.0020 in

Speeds and feeds: in mild steel an HSS drill starts at about 460 RPM and 0.0115 in/rev (5.29 IPM); in 6061 aluminum about 1,270 RPM.

3/4" drill speeds and feeds by material

Jobber-length twist drill, D = 0.7500 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

3/4" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	1,270	600	3,060	0.0110	14.0	33.7
Brass / free-machining	150	760	400	2,040	0.0090	6.84	18.4
Low-carbon steel (1018)	90	460	300	1,530	0.0115	5.29	17.6
Alloy steel (4140, annealed)	70	360	250	1,270	0.0120	4.32	15.2
Stainless 304	40	200	150	760	0.0095	1.90	7.22
Gray cast iron	80	410	250	1,270	0.0100	4.10	12.7
Titanium 6Al-4V	25	130	100	510	0.0055	0.72	2.81
Plastics (acetal)	300	1,530	500	2,550	0.0070	10.7	17.9

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 460 RPM × 0.292 mm/rev = 134 mm/min.

Worked example: 3/4" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.7500 ≈ 460 RPM.
Feed for a 0.750 in drill in mild steel ≈ 0.0115 in/rev.
IPM = 460 × 0.0115 = 5.29 IPM.

Peck cycle by hole depth

3/4" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 2.250 in (57.2 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 3.750 in (95.3 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 6.000 in (152.4 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 3/4" drill

No standard UNC, UNF or metric tap in our tables calls for a 3/4" drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

19.0 mm: 0.7480 in / 19.000 mm (-0.0020 in)
19.25 mm: 0.7579 in / 19.250 mm (+0.0079 in)
18.75 mm: 0.7382 in / 18.750 mm (-0.0118 in)
47/64": 0.7344 in / 18.653 mm (-0.0156 in)

Drill speed calculator, prefilled for 3/4"Drill finder: sizes near 3/4"Fractional drill chart Decimal equivalent chart

Common questions

What is a 3/4" drill in decimal and mm?: 0.7500 in, or 19.050 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.3370 in); nearest metric drill: 19.0 mm (0.7480 in, -0.0020 in).
What RPM for a 3/4" drill in steel?: In low-carbon steel (1018) an HSS 3/4" drill (0.7500 in) runs about 460 RPM at 90 SFM; a carbide drill about 1,530 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 3/4" drill?: About 0.0115 in/rev in mild steel, 0.0110 in/rev in aluminum and 0.0095 in/rev in 304 stainless. At 460 RPM that is 5.29 IPM in steel (IPM = RPM × IPR).
What RPM for a 3/4" drill in aluminum?: 1,270 RPM with HSS (250 SFM) or up to 3,060 RPM with carbide (600 SFM), feeding about 0.0110 in/rev.
What size is a 3/4" drill?: 0.7500 in / 19.05 mm. The nearest other drills are 19.0 mm (0.7480 in), 19.25 mm (0.7579 in), 18.75 mm (0.7382 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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