What is a 23/32" drill in decimal and mm?

0.7188 in, or 18.256 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.3058 in); nearest metric drill: 18.25 mm (0.7185 in, -0.0003 in).

What RPM for a 23/32" drill in steel?

In low-carbon steel (1018) an HSS 23/32" drill (0.7188 in) runs about 480 RPM at 90 SFM; a carbide drill about 1,590 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 23/32" drill?

About 0.0114 in/rev in mild steel, 0.0109 in/rev in aluminum and 0.0094 in/rev in 304 stainless. At 480 RPM that is 5.47 IPM in steel (IPM = RPM × IPR).

What RPM for a 23/32" drill in aluminum?

1,330 RPM with HSS (250 SFM) or up to 3,190 RPM with carbide (600 SFM), feeding about 0.0109 in/rev.

What tap uses a 23/32" drill?

3/4-16 (form (roll) tap, 65% thread); 3/4-20 (cut tap, 50% thread).

23/32" drill size

A 23/32" fractional drill is 0.7188 in (18.256 mm). It is the form (roll) tap, 65% thread drill for 3/4-16.

Decimal inch: 0.7188
Millimeters: 18.256
Nearest 1/64: 23/32" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 23/32"
System	Drill	Inch	mm	Difference
Number / letter	Letter Z	0.4130	10.490	-0.3058 in
Metric	18.25 mm	0.7185	18.250	-0.0003 in

Speeds and feeds: in mild steel an HSS drill starts at about 480 RPM and 0.0114 in/rev (5.47 IPM); in 6061 aluminum about 1,330 RPM.

23/32" drill speeds and feeds by material

Jobber-length twist drill, D = 0.7188 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

23/32" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	1,330	600	3,190	0.0109	14.5	34.8
Brass / free-machining	150	800	400	2,130	0.0089	7.12	19.0
Low-carbon steel (1018)	90	480	300	1,590	0.0114	5.47	18.1
Alloy steel (4140, annealed)	70	370	250	1,330	0.0119	4.40	15.8
Stainless 304	40	210	150	800	0.0094	1.97	7.52
Gray cast iron	80	430	250	1,330	0.0098	4.21	13.0
Titanium 6Al-4V	25	130	100	530	0.0054	0.70	2.86
Plastics (acetal)	300	1,590	500	2,660	0.0069	11.0	18.4

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 480 RPM × 0.290 mm/rev = 139 mm/min.

Worked example: 23/32" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.7188 ≈ 480 RPM.
Feed for a 0.719 in drill in mild steel ≈ 0.0114 in/rev.
IPM = 480 × 0.0114 = 5.47 IPM.

Peck cycle by hole depth

23/32" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 2.156 in (54.8 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 3.594 in (91.3 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 5.750 in (146 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 23/32" drill

3/4-16 — form (roll) tap, 65% thread · tap speeds and feeds
3/4-20 — cut tap, 50% thread

Nearest drills

18.25 mm: 0.7185 in / 18.250 mm (-0.0003 in)
18.5 mm: 0.7284 in / 18.500 mm (+0.0096 in)
18.0 mm: 0.7087 in / 18.000 mm (-0.0101 in)
45/64": 0.7031 in / 17.859 mm (-0.0156 in)

Drill speed calculator, prefilled for 23/32"Drill finder: sizes near 23/32"Fractional drill chart Decimal equivalent chart

Common questions

What is a 23/32" drill in decimal and mm?: 0.7188 in, or 18.256 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.3058 in); nearest metric drill: 18.25 mm (0.7185 in, -0.0003 in).
What RPM for a 23/32" drill in steel?: In low-carbon steel (1018) an HSS 23/32" drill (0.7188 in) runs about 480 RPM at 90 SFM; a carbide drill about 1,590 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 23/32" drill?: About 0.0114 in/rev in mild steel, 0.0109 in/rev in aluminum and 0.0094 in/rev in 304 stainless. At 480 RPM that is 5.47 IPM in steel (IPM = RPM × IPR).
What RPM for a 23/32" drill in aluminum?: 1,330 RPM with HSS (250 SFM) or up to 3,190 RPM with carbide (600 SFM), feeding about 0.0109 in/rev.
What tap uses a 23/32" drill?: 3/4-16 (form (roll) tap, 65% thread); 3/4-20 (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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