What is a #61 drill in decimal and mm?

0.0390 in, or 0.991 mm; nearest fractional drill: 1/32" (0.0313 in, -0.0077 in); nearest metric drill: 1.0 mm (0.0394 in, +0.0004 in).

What RPM for a #61 drill in steel?

In low-carbon steel (1018) an HSS #61 drill (0.0390 in) runs about 8,810 RPM at 90 SFM; a carbide drill about 29,380 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a #61 drill?

About 0.0009 in/rev in mild steel, 0.0009 in/rev in aluminum and 0.0006 in/rev in 304 stainless. At 8,810 RPM that is 7.93 IPM in steel (IPM = RPM × IPR).

What RPM for a #61 drill in aluminum?

24,490 RPM with HSS (250 SFM) or up to 58,760 RPM with carbide (600 SFM), feeding about 0.0009 in/rev.

What size is a #61 drill?

0.0390 in / 0.991 mm. The nearest other drills are 1.0 mm (0.0394 in), #62 (0.0380 in), #60 (0.0400 in).

#61 drill size

A #61 number (wire-gauge) drill is 0.0390 in (0.991 mm).

Decimal inch: 0.0390
Millimeters: 0.991
Nearest 1/64: 1/32" (+0.0077)
Type: number (wire-gauge) drill

Nearest equivalents in other systems

Drills closest to #61
System	Drill	Inch	mm	Difference
Fractional	1/32"	0.0313	0.794	-0.0077 in
Metric	1.0 mm	0.0394	1.000	+0.0004 in

Speeds and feeds: in mild steel an HSS drill starts at about 8,810 RPM and 0.0009 in/rev (7.93 IPM); in 6061 aluminum about 24,490 RPM.

#61 drill speeds and feeds by material

Jobber-length twist drill, D = 0.0390 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

#61 drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	24,490	600	58,760	0.0009	22.0	52.9
Brass / free-machining	150	14,690	400	39,180	0.0007	10.3	27.4
Low-carbon steel (1018)	90	8,810	300	29,380	0.0009	7.93	26.4
Alloy steel (4140, annealed)	70	6,860	250	24,490	0.0009	6.17	22.0
Stainless 304	40	3,920	150	14,690	0.0006	2.35	8.81
Gray cast iron	80	7,840	250	24,490	0.0006	4.70	14.7
Titanium 6Al-4V	25	2,450	100	9,790	0.0005	1.23	4.90
Plastics (acetal)	300	29,380	500	48,970	0.0016	47.0	78.3

Small drills: the computed RPM is above most spindles. Run at your spindle's maximum and keep the feed per rev; feed drops in proportion.

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 8,810 RPM × 0.023 mm/rev = 201 mm/min.

Worked example: #61 drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.0390 ≈ 8,810 RPM.
Feed for a 0.039 in drill in mild steel ≈ 0.0009 in/rev.
IPM = 8,810 × 0.0009 = 7.93 IPM.

Peck cycle by hole depth

#61 drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.117 in (3 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.195 in (5 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 0.312 in (7.9 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 #61 drill

No standard UNC, UNF or metric tap in our tables calls for a #61 drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

1.0 mm: 0.0394 in / 1.000 mm (+0.0004 in)
#62: 0.0380 in / 0.965 mm (-0.0010 in)
#60: 0.0400 in / 1.016 mm (+0.0010 in)
0.95 mm: 0.0374 in / 0.950 mm (-0.0016 in)

Drill speed calculator, prefilled for #61 Drill finder: sizes near #61 Number drill chart Decimal equivalent chart

Common questions

What is a #61 drill in decimal and mm?: 0.0390 in, or 0.991 mm; nearest fractional drill: 1/32" (0.0313 in, -0.0077 in); nearest metric drill: 1.0 mm (0.0394 in, +0.0004 in).
What RPM for a #61 drill in steel?: In low-carbon steel (1018) an HSS #61 drill (0.0390 in) runs about 8,810 RPM at 90 SFM; a carbide drill about 29,380 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a #61 drill?: About 0.0009 in/rev in mild steel, 0.0009 in/rev in aluminum and 0.0006 in/rev in 304 stainless. At 8,810 RPM that is 7.93 IPM in steel (IPM = RPM × IPR).
What RPM for a #61 drill in aluminum?: 24,490 RPM with HSS (250 SFM) or up to 58,760 RPM with carbide (600 SFM), feeding about 0.0009 in/rev.
What size is a #61 drill?: 0.0390 in / 0.991 mm. The nearest other drills are 1.0 mm (0.0394 in), #62 (0.0380 in), #60 (0.0400 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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