What is a 5/32" drill in decimal and mm?

0.1563 in, or 3.969 mm; nearest number / letter drill: #22 (0.1570 in, +0.0008 in); nearest metric drill: 4.0 mm (0.1575 in, +0.0012 in).

What RPM for a 5/32" drill in steel?

In low-carbon steel (1018) an HSS 5/32" drill (0.1563 in) runs about 2,200 RPM at 90 SFM; a carbide drill about 7,330 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 5/32" drill?

About 0.0038 in/rev in mild steel, 0.0036 in/rev in aluminum and 0.0026 in/rev in 304 stainless. At 2,200 RPM that is 8.36 IPM in steel (IPM = RPM × IPR).

What RPM for a 5/32" drill in aluminum?

6,110 RPM with HSS (250 SFM) or up to 14,670 RPM with carbide (600 SFM), feeding about 0.0036 in/rev.

What size is a 5/32" drill?

0.1563 in / 3.969 mm. The nearest other drills are #22 (0.1570 in), 4.0 mm (0.1575 in), #23 (0.1540 in).

5/32" drill size

A 5/32" fractional drill is 0.1563 in (3.969 mm).

Decimal inch: 0.1563
Millimeters: 3.969
Nearest 1/64: 5/32" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 5/32"
System	Drill	Inch	mm	Difference
Number / letter	#22	0.1570	3.988	+0.0008 in
Metric	4.0 mm	0.1575	4.000	+0.0012 in

Speeds and feeds: in mild steel an HSS drill starts at about 2,200 RPM and 0.0038 in/rev (8.36 IPM); in 6061 aluminum about 6,110 RPM.

5/32" drill speeds and feeds by material

Jobber-length twist drill, D = 0.1563 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

5/32" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	6,110	600	14,670	0.0036	22.0	52.8
Brass / free-machining	150	3,670	400	9,780	0.0031	11.4	30.3
Low-carbon steel (1018)	90	2,200	300	7,330	0.0038	8.36	27.9
Alloy steel (4140, annealed)	70	1,710	250	6,110	0.0038	6.50	23.2
Stainless 304	40	980	150	3,670	0.0026	2.55	9.54
Gray cast iron	80	1,960	250	6,110	0.0025	4.90	15.3
Titanium 6Al-4V	25	610	100	2,440	0.0019	1.16	4.64
Plastics (acetal)	300	7,330	500	12,220	0.0048	35.2	58.7

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 2,200 RPM × 0.097 mm/rev = 212 mm/min.

Worked example: 5/32" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.1563 ≈ 2,200 RPM.
Feed for a 0.156 in drill in mild steel ≈ 0.0038 in/rev.
IPM = 2,200 × 0.0038 = 8.36 IPM.

Peck cycle by hole depth

5/32" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.469 in (11.9 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.781 in (19.8 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 1.250 in (31.8 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 5/32" drill

No standard UNC, UNF or metric tap in our tables calls for a 5/32" drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

#22: 0.1570 in / 3.988 mm (+0.0008 in)
4.0 mm: 0.1575 in / 4.000 mm (+0.0012 in)
#23: 0.1540 in / 3.912 mm (-0.0022 in)
3.9 mm: 0.1535 in / 3.900 mm (-0.0027 in)

Drill speed calculator, prefilled for 5/32"Drill finder: sizes near 5/32"Fractional drill chart Decimal equivalent chart

Common questions

What is a 5/32" drill in decimal and mm?: 0.1563 in, or 3.969 mm; nearest number / letter drill: #22 (0.1570 in, +0.0008 in); nearest metric drill: 4.0 mm (0.1575 in, +0.0012 in).
What RPM for a 5/32" drill in steel?: In low-carbon steel (1018) an HSS 5/32" drill (0.1563 in) runs about 2,200 RPM at 90 SFM; a carbide drill about 7,330 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 5/32" drill?: About 0.0038 in/rev in mild steel, 0.0036 in/rev in aluminum and 0.0026 in/rev in 304 stainless. At 2,200 RPM that is 8.36 IPM in steel (IPM = RPM × IPR).
What RPM for a 5/32" drill in aluminum?: 6,110 RPM with HSS (250 SFM) or up to 14,670 RPM with carbide (600 SFM), feeding about 0.0036 in/rev.
What size is a 5/32" drill?: 0.1563 in / 3.969 mm. The nearest other drills are #22 (0.1570 in), 4.0 mm (0.1575 in), #23 (0.1540 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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