What is a #46 drill in decimal and mm?

0.0810 in, or 2.057 mm; nearest fractional drill: 5/64" (0.0781 in, -0.0029 in); nearest metric drill: 2.05 mm (0.0807 in, -0.0003 in).

What RPM for a #46 drill in steel?

In low-carbon steel (1018) an HSS #46 drill (0.0810 in) runs about 4,240 RPM at 90 SFM; a carbide drill about 14,150 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a #46 drill?

About 0.0019 in/rev in mild steel, 0.0018 in/rev in aluminum and 0.0013 in/rev in 304 stainless. At 4,240 RPM that is 8.06 IPM in steel (IPM = RPM × IPR).

What RPM for a #46 drill in aluminum?

11,790 RPM with HSS (250 SFM) or up to 28,290 RPM with carbide (600 SFM), feeding about 0.0018 in/rev.

What size is a #46 drill?

0.0810 in / 2.057 mm. The nearest other drills are 2.05 mm (0.0807 in), #45 (0.0820 in), 2.1 mm (0.0827 in).

#46 drill size

A #46 number (wire-gauge) drill is 0.0810 in (2.057 mm).

Decimal inch: 0.0810
Millimeters: 2.057
Nearest 1/64: 5/64" (+0.0029)
Type: number (wire-gauge) drill

Nearest equivalents in other systems

Drills closest to #46
System	Drill	Inch	mm	Difference
Fractional	5/64"	0.0781	1.984	-0.0029 in
Metric	2.05 mm	0.0807	2.050	-0.0003 in

Speeds and feeds: in mild steel an HSS drill starts at about 4,240 RPM and 0.0019 in/rev (8.06 IPM); in 6061 aluminum about 11,790 RPM.

#46 drill speeds and feeds by material

Jobber-length twist drill, D = 0.0810 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

#46 drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	11,790	600	28,290	0.0018	21.2	50.9
Brass / free-machining	150	7,070	400	18,860	0.0016	11.3	30.2
Low-carbon steel (1018)	90	4,240	300	14,150	0.0019	8.06	26.9
Alloy steel (4140, annealed)	70	3,300	250	11,790	0.0019	6.27	22.4
Stainless 304	40	1,890	150	7,070	0.0013	2.46	9.19
Gray cast iron	80	3,770	250	11,790	0.0012	4.52	14.2
Titanium 6Al-4V	25	1,180	100	4,720	0.0010	1.18	4.72
Plastics (acetal)	300	14,150	500	23,580	0.0032	45.3	75.5

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, 4,240 RPM × 0.048 mm/rev = 205 mm/min.

Worked example: #46 drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.0810 ≈ 4,240 RPM.
Feed for a 0.081 in drill in mild steel ≈ 0.0019 in/rev.
IPM = 4,240 × 0.0019 = 8.06 IPM.

Peck cycle by hole depth

#46 drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.243 in (6.2 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.405 in (10.3 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 0.648 in (16.5 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 #46 drill

No standard UNC, UNF or metric tap in our tables calls for a #46 drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

2.05 mm: 0.0807 in / 2.050 mm (-0.0003 in)
#45: 0.0820 in / 2.083 mm (+0.0010 in)
2.1 mm: 0.0827 in / 2.100 mm (+0.0017 in)
2.0 mm: 0.0787 in / 2.000 mm (-0.0023 in)

Drill speed calculator, prefilled for #46 Drill finder: sizes near #46 Number drill chart Decimal equivalent chart

Common questions

What is a #46 drill in decimal and mm?: 0.0810 in, or 2.057 mm; nearest fractional drill: 5/64" (0.0781 in, -0.0029 in); nearest metric drill: 2.05 mm (0.0807 in, -0.0003 in).
What RPM for a #46 drill in steel?: In low-carbon steel (1018) an HSS #46 drill (0.0810 in) runs about 4,240 RPM at 90 SFM; a carbide drill about 14,150 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a #46 drill?: About 0.0019 in/rev in mild steel, 0.0018 in/rev in aluminum and 0.0013 in/rev in 304 stainless. At 4,240 RPM that is 8.06 IPM in steel (IPM = RPM × IPR).
What RPM for a #46 drill in aluminum?: 11,790 RPM with HSS (250 SFM) or up to 28,290 RPM with carbide (600 SFM), feeding about 0.0018 in/rev.
What size is a #46 drill?: 0.0810 in / 2.057 mm. The nearest other drills are 2.05 mm (0.0807 in), #45 (0.0820 in), 2.1 mm (0.0827 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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