What is a 2.2 mm drill in decimal and mm?

0.0866 in, or 2.200 mm; nearest fractional drill: 3/32" (0.0938 in, +0.0071 in); nearest number / letter drill: #44 (0.0860 in, -0.0006 in).

What RPM for a 2.2 mm drill in steel?

In low-carbon steel (1018) an HSS 2.2 mm drill (0.0866 in) runs about 3,970 RPM at 90 SFM; a carbide drill about 13,230 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 2.2 mm drill?

About 0.0020 in/rev in mild steel, 0.0020 in/rev in aluminum and 0.0014 in/rev in 304 stainless. At 3,970 RPM that is 7.94 IPM in steel (IPM = RPM × IPR).

What RPM for a 2.2 mm drill in aluminum?

11,030 RPM with HSS (250 SFM) or up to 26,460 RPM with carbide (600 SFM), feeding about 0.0020 in/rev.

What tap uses a 2.2 mm drill?

M2.5x0.45 (cut tap, 50% thread).

2.2 mm drill size

A 2.2 mm metric drill is 0.0866 in (2.200 mm). It is the cut tap, 50% thread drill for M2.5x0.45.

Decimal inch: 0.0866
Millimeters: 2.200
Nearest 1/64: 3/32" (-0.0071)
Type: metric drill

Nearest equivalents in other systems

Drills closest to 2.2 mm
System	Drill	Inch	mm	Difference
Fractional	3/32"	0.0938	2.381	+0.0071 in
Number / letter	#44	0.0860	2.184	-0.0006 in

Speeds and feeds: in mild steel an HSS drill starts at about 3,970 RPM and 0.0020 in/rev (7.94 IPM); in 6061 aluminum about 11,030 RPM.

2.2 mm drill speeds and feeds by material

Jobber-length twist drill, D = 0.0866 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

2.2 mm drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	11,030	600	26,460	0.0020	22.1	52.9
Brass / free-machining	150	6,620	400	17,640	0.0017	11.3	30.0
Low-carbon steel (1018)	90	3,970	300	13,230	0.0020	7.94	26.5
Alloy steel (4140, annealed)	70	3,090	250	11,030	0.0020	6.18	22.1
Stainless 304	40	1,760	150	6,620	0.0014	2.46	9.27
Gray cast iron	80	3,530	250	11,030	0.0012	4.24	13.2
Titanium 6Al-4V	25	1,100	100	4,410	0.0011	1.21	4.85
Plastics (acetal)	300	13,230	500	22,050	0.0035	46.3	77.2

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, 3,970 RPM × 0.051 mm/rev = 202 mm/min.

Worked example: 2.2 mm drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.0866 ≈ 3,970 RPM.
Feed for a 0.087 in drill in mild steel ≈ 0.0020 in/rev.
IPM = 3,970 × 0.0020 = 7.94 IPM.

Peck cycle by hole depth

2.2 mm drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.260 in (6.6 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.433 in (11 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 0.693 in (17.6 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 2.2 mm drill

M2.5x0.45 — cut tap, 50% thread · tap speeds and feeds

Nearest drills

#44: 0.0860 in / 2.184 mm (-0.0006 in)
2.15 mm: 0.0847 in / 2.150 mm (-0.0020 in)
2.25 mm: 0.0886 in / 2.250 mm (+0.0020 in)
#43: 0.0890 in / 2.261 mm (+0.0024 in)

Drill speed calculator, prefilled for 2.2 mm Drill finder: sizes near 2.2 mm Metric drill chart Decimal equivalent chart

Common questions

What is a 2.2 mm drill in decimal and mm?: 0.0866 in, or 2.200 mm; nearest fractional drill: 3/32" (0.0938 in, +0.0071 in); nearest number / letter drill: #44 (0.0860 in, -0.0006 in).
What RPM for a 2.2 mm drill in steel?: In low-carbon steel (1018) an HSS 2.2 mm drill (0.0866 in) runs about 3,970 RPM at 90 SFM; a carbide drill about 13,230 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 2.2 mm drill?: About 0.0020 in/rev in mild steel, 0.0020 in/rev in aluminum and 0.0014 in/rev in 304 stainless. At 3,970 RPM that is 7.94 IPM in steel (IPM = RPM × IPR).
What RPM for a 2.2 mm drill in aluminum?: 11,030 RPM with HSS (250 SFM) or up to 26,460 RPM with carbide (600 SFM), feeding about 0.0020 in/rev.
What tap uses a 2.2 mm drill?: M2.5x0.45 (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.

Free for machinists & programmers

Put your skills on a free talent profile

Machines, controls, certs and saved calculations in one profile shops can find.

Create free profile

For your shop

Bring shift handoffs to your shop

Stop losing job status between shifts. Every station's notes, counts and issues, handed off cleanly.

See shift handoffs