What is a 3.7 mm drill in decimal and mm?

0.1457 in, or 3.700 mm; nearest fractional drill: 9/64" (0.1406 in, -0.0050 in); nearest number / letter drill: #26 (0.1470 in, +0.0013 in).

What RPM for a 3.7 mm drill in steel?

In low-carbon steel (1018) an HSS 3.7 mm drill (0.1457 in) runs about 2,360 RPM at 90 SFM; a carbide drill about 7,870 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 3.7 mm drill?

About 0.0035 in/rev in mild steel, 0.0034 in/rev in aluminum and 0.0024 in/rev in 304 stainless. At 2,360 RPM that is 8.26 IPM in steel (IPM = RPM × IPR).

What RPM for a 3.7 mm drill in aluminum?

6,560 RPM with HSS (250 SFM) or up to 15,730 RPM with carbide (600 SFM), feeding about 0.0034 in/rev.

What tap uses a 3.7 mm drill?

M4×0.7 (form (roll) tap, 65% thread); M4x0.5 (cut tap, 50% thread).

3.7 mm drill size

A 3.7 mm metric drill is 0.1457 in (3.700 mm). It is the form (roll) tap, 65% thread drill for M4×0.7.

Decimal inch: 0.1457
Millimeters: 3.700
Nearest 1/64: 9/64" (+0.0050)
Type: metric drill

Nearest equivalents in other systems

Drills closest to 3.7 mm
System	Drill	Inch	mm	Difference
Fractional	9/64"	0.1406	3.572	-0.0050 in
Number / letter	#26	0.1470	3.734	+0.0013 in

Speeds and feeds: in mild steel an HSS drill starts at about 2,360 RPM and 0.0035 in/rev (8.26 IPM); in 6061 aluminum about 6,560 RPM.

3.7 mm drill speeds and feeds by material

Jobber-length twist drill, D = 0.1457 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

3.7 mm drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	6,560	600	15,730	0.0034	22.3	53.5
Brass / free-machining	150	3,930	400	10,490	0.0029	11.4	30.4
Low-carbon steel (1018)	90	2,360	300	7,870	0.0035	8.26	27.6
Alloy steel (4140, annealed)	70	1,840	250	6,560	0.0035	6.44	23.0
Stainless 304	40	1,050	150	3,930	0.0024	2.52	9.43
Gray cast iron	80	2,100	250	6,560	0.0022	4.62	14.4
Titanium 6Al-4V	25	660	100	2,620	0.0018	1.19	4.72
Plastics (acetal)	300	7,870	500	13,110	0.0048	37.8	62.9

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 2,360 RPM × 0.089 mm/rev = 210 mm/min.

Worked example: 3.7 mm drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.1457 ≈ 2,360 RPM.
Feed for a 0.146 in drill in mild steel ≈ 0.0035 in/rev.
IPM = 2,360 × 0.0035 = 8.26 IPM.

Peck cycle by hole depth

3.7 mm drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.437 in (11.1 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.728 in (18.5 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 1.165 in (29.6 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 3.7 mm drill

M4×0.7 — form (roll) tap, 65% thread · tap speeds and feeds
M4x0.5 — cut tap, 50% thread

Nearest drills

#26: 0.1470 in / 3.734 mm (+0.0013 in)
#27: 0.1440 in / 3.658 mm (-0.0017 in)
#25: 0.1495 in / 3.797 mm (+0.0038 in)
3.6 mm: 0.1417 in / 3.600 mm (-0.0039 in)

Drill speed calculator, prefilled for 3.7 mm Drill finder: sizes near 3.7 mm Metric drill chart Decimal equivalent chart

Common questions

What is a 3.7 mm drill in decimal and mm?: 0.1457 in, or 3.700 mm; nearest fractional drill: 9/64" (0.1406 in, -0.0050 in); nearest number / letter drill: #26 (0.1470 in, +0.0013 in).
What RPM for a 3.7 mm drill in steel?: In low-carbon steel (1018) an HSS 3.7 mm drill (0.1457 in) runs about 2,360 RPM at 90 SFM; a carbide drill about 7,870 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 3.7 mm drill?: About 0.0035 in/rev in mild steel, 0.0034 in/rev in aluminum and 0.0024 in/rev in 304 stainless. At 2,360 RPM that is 8.26 IPM in steel (IPM = RPM × IPR).
What RPM for a 3.7 mm drill in aluminum?: 6,560 RPM with HSS (250 SFM) or up to 15,730 RPM with carbide (600 SFM), feeding about 0.0034 in/rev.
What tap uses a 3.7 mm drill?: M4×0.7 (form (roll) tap, 65% thread); M4x0.5 (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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