What is a 9/16" drill in decimal and mm?

0.5625 in, or 14.288 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.1495 in); nearest metric drill: 14.25 mm (0.5610 in, -0.0015 in).

What RPM for a 9/16" drill in steel?

In low-carbon steel (1018) an HSS 9/16" drill (0.5625 in) runs about 610 RPM at 90 SFM; a carbide drill about 2,040 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 9/16" drill?

About 0.0107 in/rev in mild steel, 0.0103 in/rev in aluminum and 0.0088 in/rev in 304 stainless. At 610 RPM that is 6.53 IPM in steel (IPM = RPM × IPR).

What RPM for a 9/16" drill in aluminum?

1,700 RPM with HSS (250 SFM) or up to 4,070 RPM with carbide (600 SFM), feeding about 0.0103 in/rev.

9/16" drill size

A 9/16" fractional drill is 0.5625 in (14.288 mm). It is the cut tap, 50% thread drill for 5/8-11.

Decimal inch: 0.5625
Millimeters: 14.288
Nearest 1/64: 9/16" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 9/16"
System	Drill	Inch	mm	Difference
Number / letter	Letter Z	0.4130	10.490	-0.1495 in
Metric	14.25 mm	0.5610	14.250	-0.0015 in

Speeds and feeds: in mild steel an HSS drill starts at about 610 RPM and 0.0107 in/rev (6.53 IPM); in 6061 aluminum about 1,700 RPM.

9/16" drill speeds and feeds by material

Jobber-length twist drill, D = 0.5625 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

9/16" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	1,700	600	4,070	0.0103	17.5	41.9
Brass / free-machining	150	1,020	400	2,720	0.0084	8.57	22.9
Low-carbon steel (1018)	90	610	300	2,040	0.0107	6.53	21.8
Alloy steel (4140, annealed)	70	480	250	1,700	0.0116	5.57	19.7
Stainless 304	40	270	150	1,020	0.0088	2.38	8.98
Gray cast iron	80	540	250	1,700	0.0089	4.81	15.1
Titanium 6Al-4V	25	170	100	680	0.0051	0.87	3.47
Plastics (acetal)	300	2,040	500	3,400	0.0063	12.8	21.4

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 610 RPM × 0.272 mm/rev = 166 mm/min.

Worked example: 9/16" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.5625 ≈ 610 RPM.
Feed for a 0.563 in drill in mild steel ≈ 0.0107 in/rev.
IPM = 610 × 0.0107 = 6.53 IPM.

Peck cycle by hole depth

9/16" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 1.688 in (42.9 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 2.813 in (71.4 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 4.500 in (114.3 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 9/16" drill

5/8-11 — cut tap, 50% thread · tap speeds and feeds

Nearest drills

14.25 mm: 0.5610 in / 14.250 mm (-0.0015 in)
14.5 mm: 0.5709 in / 14.500 mm (+0.0084 in)
14.0 mm: 0.5512 in / 14.000 mm (-0.0113 in)
13.9 mm: 0.5472 in / 13.900 mm (-0.0153 in)

Drill speed calculator, prefilled for 9/16"Drill finder: sizes near 9/16"Fractional drill chart Decimal equivalent chart

Common questions

What is a 9/16" drill in decimal and mm?: 0.5625 in, or 14.288 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.1495 in); nearest metric drill: 14.25 mm (0.5610 in, -0.0015 in).
What RPM for a 9/16" drill in steel?: In low-carbon steel (1018) an HSS 9/16" drill (0.5625 in) runs about 610 RPM at 90 SFM; a carbide drill about 2,040 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 9/16" drill?: About 0.0107 in/rev in mild steel, 0.0103 in/rev in aluminum and 0.0088 in/rev in 304 stainless. At 610 RPM that is 6.53 IPM in steel (IPM = RPM × IPR).
What RPM for a 9/16" drill in aluminum?: 1,700 RPM with HSS (250 SFM) or up to 4,070 RPM with carbide (600 SFM), feeding about 0.0103 in/rev.
What tap uses a 9/16" drill?: 5/8-11 (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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