What is a 7/32" drill in decimal and mm?

0.2188 in, or 5.556 mm; nearest number / letter drill: #2 (0.2210 in, +0.0022 in); nearest metric drill: 5.6 mm (0.2205 in, +0.0017 in).

What RPM for a 7/32" drill in steel?

In low-carbon steel (1018) an HSS 7/32" drill (0.2188 in) runs about 1,570 RPM at 90 SFM; a carbide drill about 5,240 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 7/32" drill?

About 0.0056 in/rev in mild steel, 0.0052 in/rev in aluminum and 0.0037 in/rev in 304 stainless. At 1,570 RPM that is 8.79 IPM in steel (IPM = RPM × IPR).

What RPM for a 7/32" drill in aluminum?

4,370 RPM with HSS (250 SFM) or up to 10,480 RPM with carbide (600 SFM), feeding about 0.0052 in/rev.

What tap uses a 7/32" drill?

1/4-32 (cut tap, 75% thread); 1/4-20 (cut tap, 50% thread).

7/32" drill size

A 7/32" fractional drill is 0.2188 in (5.556 mm). It is the cut tap, 75% thread drill for 1/4-32.

Decimal inch: 0.2188
Millimeters: 5.556
Nearest 1/64: 7/32" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 7/32"
System	Drill	Inch	mm	Difference
Number / letter	#2	0.2210	5.613	+0.0022 in
Metric	5.6 mm	0.2205	5.600	+0.0017 in

Speeds and feeds: in mild steel an HSS drill starts at about 1,570 RPM and 0.0056 in/rev (8.79 IPM); in 6061 aluminum about 4,370 RPM.

7/32" drill speeds and feeds by material

Jobber-length twist drill, D = 0.2188 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

7/32" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	4,370	600	10,480	0.0052	22.7	54.5
Brass / free-machining	150	2,620	400	6,980	0.0045	11.8	31.4
Low-carbon steel (1018)	90	1,570	300	5,240	0.0056	8.79	29.3
Alloy steel (4140, annealed)	70	1,220	250	4,370	0.0056	6.83	24.5
Stainless 304	40	700	150	2,620	0.0037	2.59	9.69
Gray cast iron	80	1,400	250	4,370	0.0038	5.32	16.6
Titanium 6Al-4V	25	440	100	1,750	0.0026	1.14	4.55
Plastics (acetal)	300	5,240	500	8,730	0.0043	22.5	37.5

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 1,570 RPM × 0.142 mm/rev = 223 mm/min.

Worked example: 7/32" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.2188 ≈ 1,570 RPM.
Feed for a 0.219 in drill in mild steel ≈ 0.0056 in/rev.
IPM = 1,570 × 0.0056 = 8.79 IPM.

Peck cycle by hole depth

7/32" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.656 in (16.7 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 1.094 in (27.8 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 1.750 in (44.4 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 7/32" drill

1/4-32 — cut tap, 75% thread
1/4-20 — cut tap, 50% thread · tap speeds and feeds

Nearest drills

5.6 mm: 0.2205 in / 5.600 mm (+0.0017 in)
5.5 mm: 0.2165 in / 5.500 mm (-0.0022 in)
#2: 0.2210 in / 5.613 mm (+0.0022 in)
5.7 mm: 0.2244 in / 5.700 mm (+0.0057 in)

Drill speed calculator, prefilled for 7/32"Drill finder: sizes near 7/32"Fractional drill chart Decimal equivalent chart

Common questions

What is a 7/32" drill in decimal and mm?: 0.2188 in, or 5.556 mm; nearest number / letter drill: #2 (0.2210 in, +0.0022 in); nearest metric drill: 5.6 mm (0.2205 in, +0.0017 in).
What RPM for a 7/32" drill in steel?: In low-carbon steel (1018) an HSS 7/32" drill (0.2188 in) runs about 1,570 RPM at 90 SFM; a carbide drill about 5,240 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 7/32" drill?: About 0.0056 in/rev in mild steel, 0.0052 in/rev in aluminum and 0.0037 in/rev in 304 stainless. At 1,570 RPM that is 8.79 IPM in steel (IPM = RPM × IPR).
What RPM for a 7/32" drill in aluminum?: 4,370 RPM with HSS (250 SFM) or up to 10,480 RPM with carbide (600 SFM), feeding about 0.0052 in/rev.
What tap uses a 7/32" drill?: 1/4-32 (cut tap, 75% thread); 1/4-20 (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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