What is a 2.05 mm drill in decimal and mm?

0.0807 in, or 2.050 mm; nearest fractional drill: 5/64" (0.0781 in, -0.0026 in); nearest number / letter drill: #46 (0.0810 in, +0.0003 in).

What RPM for a 2.05 mm drill in steel?

In low-carbon steel (1018) an HSS 2.05 mm drill (0.0807 in) runs about 4,260 RPM at 90 SFM; a carbide drill about 14,200 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 2.05 mm drill?

About 0.0019 in/rev in mild steel, 0.0018 in/rev in aluminum and 0.0013 in/rev in 304 stainless. At 4,260 RPM that is 8.09 IPM in steel (IPM = RPM × IPR).

What RPM for a 2.05 mm drill in aluminum?

11,830 RPM with HSS (250 SFM) or up to 28,400 RPM with carbide (600 SFM), feeding about 0.0018 in/rev.

What tap uses a 2.05 mm drill?

M2.5x0.45 (cut tap, 75% thread).

2.05 mm drill size

A 2.05 mm metric drill is 0.0807 in (2.050 mm). It is the cut tap, 75% thread drill for M2.5x0.45.

Decimal inch: 0.0807
Millimeters: 2.050
Nearest 1/64: 5/64" (+0.0026)
Type: metric drill

Nearest equivalents in other systems

Drills closest to 2.05 mm
System	Drill	Inch	mm	Difference
Fractional	5/64"	0.0781	1.984	-0.0026 in
Number / letter	#46	0.0810	2.057	+0.0003 in

Speeds and feeds: in mild steel an HSS drill starts at about 4,260 RPM and 0.0019 in/rev (8.09 IPM); in 6061 aluminum about 11,830 RPM.

2.05 mm drill speeds and feeds by material

Jobber-length twist drill, D = 0.0807 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

2.05 mm drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	11,830	600	28,400	0.0018	21.3	51.1
Brass / free-machining	150	7,100	400	18,930	0.0015	10.7	28.4
Low-carbon steel (1018)	90	4,260	300	14,200	0.0019	8.09	27.0
Alloy steel (4140, annealed)	70	3,310	250	11,830	0.0019	6.29	22.5
Stainless 304	40	1,890	150	7,100	0.0013	2.46	9.23
Gray cast iron	80	3,790	250	11,830	0.0012	4.55	14.2
Titanium 6Al-4V	25	1,180	100	4,730	0.0010	1.18	4.73
Plastics (acetal)	300	14,200	500	23,660	0.0032	45.4	75.7

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, 4,260 RPM × 0.048 mm/rev = 206 mm/min.

Worked example: 2.05 mm drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.0807 ≈ 4,260 RPM.
Feed for a 0.081 in drill in mild steel ≈ 0.0019 in/rev.
IPM = 4,260 × 0.0019 = 8.09 IPM.

Peck cycle by hole depth

2.05 mm drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.242 in (6.1 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.404 in (10.3 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 0.646 in (16.4 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 2.05 mm drill

M2.5x0.45 — cut tap, 75% thread · tap speeds and feeds

Nearest drills

#46: 0.0810 in / 2.057 mm (+0.0003 in)
#45: 0.0820 in / 2.083 mm (+0.0013 in)
2.0 mm: 0.0787 in / 2.000 mm (-0.0020 in)
2.1 mm: 0.0827 in / 2.100 mm (+0.0020 in)

Drill speed calculator, prefilled for 2.05 mm Drill finder: sizes near 2.05 mm Metric drill chart Decimal equivalent chart

Common questions

What is a 2.05 mm drill in decimal and mm?: 0.0807 in, or 2.050 mm; nearest fractional drill: 5/64" (0.0781 in, -0.0026 in); nearest number / letter drill: #46 (0.0810 in, +0.0003 in).
What RPM for a 2.05 mm drill in steel?: In low-carbon steel (1018) an HSS 2.05 mm drill (0.0807 in) runs about 4,260 RPM at 90 SFM; a carbide drill about 14,200 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 2.05 mm drill?: About 0.0019 in/rev in mild steel, 0.0018 in/rev in aluminum and 0.0013 in/rev in 304 stainless. At 4,260 RPM that is 8.09 IPM in steel (IPM = RPM × IPR).
What RPM for a 2.05 mm drill in aluminum?: 11,830 RPM with HSS (250 SFM) or up to 28,400 RPM with carbide (600 SFM), feeding about 0.0018 in/rev.
What tap uses a 2.05 mm drill?: M2.5x0.45 (cut tap, 75% 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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