What is a 1.75 mm drill in decimal and mm?

0.0689 in, or 1.750 mm; nearest fractional drill: 1/16" (0.0625 in, -0.0064 in); nearest number / letter drill: #50 (0.0700 in, +0.0011 in).

What RPM for a 1.75 mm drill in steel?

In low-carbon steel (1018) an HSS 1.75 mm drill (0.0689 in) runs about 4,990 RPM at 90 SFM; a carbide drill about 16,630 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 1.75 mm drill?

About 0.0016 in/rev in mild steel, 0.0016 in/rev in aluminum and 0.0011 in/rev in 304 stainless. At 4,990 RPM that is 7.98 IPM in steel (IPM = RPM × IPR).

What RPM for a 1.75 mm drill in aluminum?

13,860 RPM with HSS (250 SFM) or up to 33,260 RPM with carbide (600 SFM), feeding about 0.0016 in/rev.

1.75 mm drill size

A 1.75 mm metric drill is 0.0689 in (1.750 mm). It is the cut tap, 50% thread drill for M2x0.4.

Decimal inch: 0.0689
Millimeters: 1.750
Nearest 1/64: 1/16" (+0.0064)
Type: metric drill

Nearest equivalents in other systems

Drills closest to 1.75 mm
System	Drill	Inch	mm	Difference
Fractional	1/16"	0.0625	1.588	-0.0064 in
Number / letter	#50	0.0700	1.778	+0.0011 in

Speeds and feeds: in mild steel an HSS drill starts at about 4,990 RPM and 0.0016 in/rev (7.98 IPM); in 6061 aluminum about 13,860 RPM.

1.75 mm drill speeds and feeds by material

Jobber-length twist drill, D = 0.0689 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

1.75 mm drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	13,860	600	33,260	0.0016	22.2	53.2
Brass / free-machining	150	8,320	400	22,180	0.0013	10.8	28.8
Low-carbon steel (1018)	90	4,990	300	16,630	0.0016	7.98	26.6
Alloy steel (4140, annealed)	70	3,880	250	13,860	0.0016	6.21	22.2
Stainless 304	40	2,220	150	8,320	0.0011	2.44	9.15
Gray cast iron	80	4,440	250	13,860	0.0010	4.44	13.9
Titanium 6Al-4V	25	1,390	100	5,540	0.0009	1.25	4.99
Plastics (acetal)	300	16,630	500	27,720	0.0028	46.6	77.6

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, 4,990 RPM × 0.041 mm/rev = 203 mm/min.

Worked example: 1.75 mm drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.0689 ≈ 4,990 RPM.
Feed for a 0.069 in drill in mild steel ≈ 0.0016 in/rev.
IPM = 4,990 × 0.0016 = 7.98 IPM.

Peck cycle by hole depth

1.75 mm drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.207 in (5.3 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.345 in (8.8 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 0.551 in (14 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 1.75 mm drill

M2x0.4 — cut tap, 50% thread · tap speeds and feeds

Nearest drills

#50: 0.0700 in / 1.778 mm (+0.0011 in)
#51: 0.0670 in / 1.702 mm (-0.0019 in)
1.7 mm: 0.0669 in / 1.700 mm (-0.0020 in)
1.8 mm: 0.0709 in / 1.800 mm (+0.0020 in)

Drill speed calculator, prefilled for 1.75 mm Drill finder: sizes near 1.75 mm Metric drill chart Decimal equivalent chart

Common questions

What is a 1.75 mm drill in decimal and mm?: 0.0689 in, or 1.750 mm; nearest fractional drill: 1/16" (0.0625 in, -0.0064 in); nearest number / letter drill: #50 (0.0700 in, +0.0011 in).
What RPM for a 1.75 mm drill in steel?: In low-carbon steel (1018) an HSS 1.75 mm drill (0.0689 in) runs about 4,990 RPM at 90 SFM; a carbide drill about 16,630 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 1.75 mm drill?: About 0.0016 in/rev in mild steel, 0.0016 in/rev in aluminum and 0.0011 in/rev in 304 stainless. At 4,990 RPM that is 7.98 IPM in steel (IPM = RPM × IPR).
What RPM for a 1.75 mm drill in aluminum?: 13,860 RPM with HSS (250 SFM) or up to 33,260 RPM with carbide (600 SFM), feeding about 0.0016 in/rev.
What tap uses a 1.75 mm drill?: M2x0.4 (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.

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