What is a #6 drill in decimal and mm?

0.2040 in, or 5.182 mm; nearest fractional drill: 13/64" (0.2031 in, -0.0009 in); nearest metric drill: 5.2 mm (0.2047 in, +0.0007 in).

What RPM for a #6 drill in steel?

In low-carbon steel (1018) an HSS #6 drill (0.2040 in) runs about 1,690 RPM at 90 SFM; a carbide drill about 5,620 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a #6 drill?

About 0.0052 in/rev in mild steel, 0.0048 in/rev in aluminum and 0.0034 in/rev in 304 stainless. At 1,690 RPM that is 8.79 IPM in steel (IPM = RPM × IPR).

What RPM for a #6 drill in aluminum?

4,680 RPM with HSS (250 SFM) or up to 11,230 RPM with carbide (600 SFM), feeding about 0.0048 in/rev.

What size is a #6 drill?

0.2040 in / 5.182 mm. The nearest other drills are 5.2 mm (0.2047 in), 13/64" (0.2031 in), #5 (0.2055 in).

#6 drill size

A #6 number (wire-gauge) drill is 0.2040 in (5.182 mm).

Decimal inch: 0.2040
Millimeters: 5.182
Nearest 1/64: 13/64" (+0.0009)
Type: number (wire-gauge) drill

Nearest equivalents in other systems

Drills closest to #6
System	Drill	Inch	mm	Difference
Fractional	13/64"	0.2031	5.159	-0.0009 in
Metric	5.2 mm	0.2047	5.200	+0.0007 in

Speeds and feeds: in mild steel an HSS drill starts at about 1,690 RPM and 0.0052 in/rev (8.79 IPM); in 6061 aluminum about 4,680 RPM.

#6 drill speeds and feeds by material

Jobber-length twist drill, D = 0.2040 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

#6 drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	4,680	600	11,230	0.0048	22.5	53.9
Brass / free-machining	150	2,810	400	7,490	0.0042	11.8	31.5
Low-carbon steel (1018)	90	1,690	300	5,620	0.0052	8.79	29.2
Alloy steel (4140, annealed)	70	1,310	250	4,680	0.0052	6.81	24.3
Stainless 304	40	750	150	2,810	0.0034	2.55	9.55
Gray cast iron	80	1,500	250	4,680	0.0035	5.25	16.4
Titanium 6Al-4V	25	470	100	1,870	0.0025	1.18	4.68
Plastics (acetal)	300	5,620	500	9,360	0.0044	24.7	41.2

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 1,690 RPM × 0.132 mm/rev = 223 mm/min.

Worked example: #6 drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.2040 ≈ 1,690 RPM.
Feed for a 0.204 in drill in mild steel ≈ 0.0052 in/rev.
IPM = 1,690 × 0.0052 = 8.79 IPM.

Peck cycle by hole depth

#6 drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.612 in (15.5 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 1.020 in (25.9 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 1.632 in (41.5 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 #6 drill

No standard UNC, UNF or metric tap in our tables calls for a #6 drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

5.2 mm: 0.2047 in / 5.200 mm (+0.0007 in)
13/64": 0.2031 in / 5.159 mm (-0.0009 in)
#5: 0.2055 in / 5.220 mm (+0.0015 in)
#7: 0.2010 in / 5.105 mm (-0.0030 in)

Drill speed calculator, prefilled for #6 Drill finder: sizes near #6 Number drill chart Decimal equivalent chart

Common questions

What is a #6 drill in decimal and mm?: 0.2040 in, or 5.182 mm; nearest fractional drill: 13/64" (0.2031 in, -0.0009 in); nearest metric drill: 5.2 mm (0.2047 in, +0.0007 in).
What RPM for a #6 drill in steel?: In low-carbon steel (1018) an HSS #6 drill (0.2040 in) runs about 1,690 RPM at 90 SFM; a carbide drill about 5,620 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a #6 drill?: About 0.0052 in/rev in mild steel, 0.0048 in/rev in aluminum and 0.0034 in/rev in 304 stainless. At 1,690 RPM that is 8.79 IPM in steel (IPM = RPM × IPR).
What RPM for a #6 drill in aluminum?: 4,680 RPM with HSS (250 SFM) or up to 11,230 RPM with carbide (600 SFM), feeding about 0.0048 in/rev.
What size is a #6 drill?: 0.2040 in / 5.182 mm. The nearest other drills are 5.2 mm (0.2047 in), 13/64" (0.2031 in), #5 (0.2055 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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