What is a 4.5 mm drill in decimal and mm?

0.1772 in, or 4.500 mm; nearest fractional drill: 11/64" (0.1719 in, -0.0053 in); nearest number / letter drill: #16 (0.1770 in, -0.0002 in).

What RPM for a 4.5 mm drill in steel?

In low-carbon steel (1018) an HSS 4.5 mm drill (0.1772 in) runs about 1,940 RPM at 90 SFM; a carbide drill about 6,470 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 4.5 mm drill?

About 0.0044 in/rev in mild steel, 0.0042 in/rev in aluminum and 0.0029 in/rev in 304 stainless. At 1,940 RPM that is 8.54 IPM in steel (IPM = RPM × IPR).

What RPM for a 4.5 mm drill in aluminum?

5,390 RPM with HSS (250 SFM) or up to 12,940 RPM with carbide (600 SFM), feeding about 0.0042 in/rev.

What tap uses a 4.5 mm drill?

M5x0.5 (cut tap, 75% thread); M5×0.8 (cut tap, 50% thread); M4×0.7 (Helicoil / STI insert (M4×0.7×1D)).

4.5 mm drill size

A 4.5 mm metric drill is 0.1772 in (4.500 mm). It is the cut tap, 75% thread drill for M5x0.5.

Decimal inch: 0.1772
Millimeters: 4.500
Nearest 1/64: 11/64" (+0.0053)
Type: metric drill

Nearest equivalents in other systems

Drills closest to 4.5 mm
System	Drill	Inch	mm	Difference
Fractional	11/64"	0.1719	4.366	-0.0053 in
Number / letter	#16	0.1770	4.496	-0.0002 in

Speeds and feeds: in mild steel an HSS drill starts at about 1,940 RPM and 0.0044 in/rev (8.54 IPM); in 6061 aluminum about 5,390 RPM.

4.5 mm drill speeds and feeds by material

Jobber-length twist drill, D = 0.1772 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

4.5 mm drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	5,390	600	12,940	0.0042	22.6	54.4
Brass / free-machining	150	3,230	400	8,620	0.0036	11.6	31.0
Low-carbon steel (1018)	90	1,940	300	6,470	0.0044	8.54	28.5
Alloy steel (4140, annealed)	70	1,510	250	5,390	0.0044	6.64	23.7
Stainless 304	40	860	150	3,230	0.0029	2.49	9.37
Gray cast iron	80	1,720	250	5,390	0.0029	4.99	15.6
Titanium 6Al-4V	25	540	100	2,160	0.0022	1.19	4.75
Plastics (acetal)	300	6,470	500	10,780	0.0046	29.8	49.6

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 1,940 RPM × 0.112 mm/rev = 217 mm/min.

Worked example: 4.5 mm drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.1772 ≈ 1,940 RPM.
Feed for a 0.177 in drill in mild steel ≈ 0.0044 in/rev.
IPM = 1,940 × 0.0044 = 8.54 IPM.

Peck cycle by hole depth

4.5 mm drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.532 in (13.5 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 0.886 in (22.5 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 1.417 in (36 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 4.5 mm drill

M5x0.5 — cut tap, 75% thread
M5×0.8 — cut tap, 50% thread · tap speeds and feeds
M4×0.7 — Helicoil / STI insert (M4×0.7×1D) · tap speeds and feeds

Nearest drills

#16: 0.1770 in / 4.496 mm (-0.0002 in)
#15: 0.1800 in / 4.572 mm (+0.0028 in)
4.6 mm: 0.1811 in / 4.600 mm (+0.0039 in)
4.4 mm: 0.1732 in / 4.400 mm (-0.0039 in)

Drill speed calculator, prefilled for 4.5 mm Drill finder: sizes near 4.5 mm Metric drill chart Decimal equivalent chart

Common questions

What is a 4.5 mm drill in decimal and mm?: 0.1772 in, or 4.500 mm; nearest fractional drill: 11/64" (0.1719 in, -0.0053 in); nearest number / letter drill: #16 (0.1770 in, -0.0002 in).
What RPM for a 4.5 mm drill in steel?: In low-carbon steel (1018) an HSS 4.5 mm drill (0.1772 in) runs about 1,940 RPM at 90 SFM; a carbide drill about 6,470 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 4.5 mm drill?: About 0.0044 in/rev in mild steel, 0.0042 in/rev in aluminum and 0.0029 in/rev in 304 stainless. At 1,940 RPM that is 8.54 IPM in steel (IPM = RPM × IPR).
What RPM for a 4.5 mm drill in aluminum?: 5,390 RPM with HSS (250 SFM) or up to 12,940 RPM with carbide (600 SFM), feeding about 0.0042 in/rev.
What tap uses a 4.5 mm drill?: M5x0.5 (cut tap, 75% thread); M5×0.8 (cut tap, 50% thread); M4×0.7 (Helicoil / STI insert (M4×0.7×1D)).

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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