What is a 11.5 mm drill in decimal and mm?

0.4528 in, or 11.500 mm; nearest fractional drill: 29/64" (0.4531 in, +0.0004 in); nearest number / letter drill: Letter Z (0.4130 in, -0.0398 in).

What RPM for a 11.5 mm drill in steel?

In low-carbon steel (1018) an HSS 11.5 mm drill (0.4528 in) runs about 760 RPM at 90 SFM; a carbide drill about 2,530 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 11.5 mm drill?

About 0.0101 in/rev in mild steel, 0.0094 in/rev in aluminum and 0.0076 in/rev in 304 stainless. At 760 RPM that is 7.68 IPM in steel (IPM = RPM × IPR).

What RPM for a 11.5 mm drill in aluminum?

2,110 RPM with HSS (250 SFM) or up to 5,060 RPM with carbide (600 SFM), feeding about 0.0094 in/rev.

What size is a 11.5 mm drill?

0.4528 in / 11.50 mm. The nearest other drills are 29/64" (0.4531 in), 11.6 mm (0.4567 in), 11.4 mm (0.4488 in).

11.5 mm drill size

A 11.5 mm metric drill is 0.4528 in (11.500 mm).

Decimal inch: 0.4528
Millimeters: 11.500
Nearest 1/64: 29/64" (-0.0004)
Type: metric drill

Nearest equivalents in other systems

Drills closest to 11.5 mm
System	Drill	Inch	mm	Difference
Fractional	29/64"	0.4531	11.509	+0.0004 in
Number / letter	Letter Z	0.4130	10.490	-0.0398 in

Speeds and feeds: in mild steel an HSS drill starts at about 760 RPM and 0.0101 in/rev (7.68 IPM); in 6061 aluminum about 2,110 RPM.

11.5 mm drill speeds and feeds by material

Jobber-length twist drill, D = 0.4528 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

11.5 mm drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	2,110	600	5,060	0.0094	19.8	47.6
Brass / free-machining	150	1,270	400	3,370	0.0075	9.53	25.3
Low-carbon steel (1018)	90	760	300	2,530	0.0101	7.68	25.6
Alloy steel (4140, annealed)	70	590	250	2,110	0.0111	6.55	23.4
Stainless 304	40	340	150	1,270	0.0076	2.58	9.65
Gray cast iron	80	670	250	2,110	0.0077	5.16	16.3
Titanium 6Al-4V	25	210	100	840	0.0047	0.99	3.95
Plastics (acetal)	300	2,530	500	4,220	0.0056	14.2	23.6

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 760 RPM × 0.257 mm/rev = 195 mm/min.

Worked example: 11.5 mm drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.4528 ≈ 760 RPM.
Feed for a 0.453 in drill in mild steel ≈ 0.0101 in/rev.
IPM = 760 × 0.0101 = 7.68 IPM.

Peck cycle by hole depth

11.5 mm drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 1.358 in (34.5 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 2.264 in (57.5 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 3.622 in (92 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 11.5 mm drill

No standard UNC, UNF or metric tap in our tables calls for a 11.5 mm drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

29/64": 0.4531 in / 11.509 mm (+0.0004 in)
11.6 mm: 0.4567 in / 11.600 mm (+0.0039 in)
11.4 mm: 0.4488 in / 11.400 mm (-0.0039 in)
11.7 mm: 0.4606 in / 11.700 mm (+0.0079 in)

Drill speed calculator, prefilled for 11.5 mm Drill finder: sizes near 11.5 mm Metric drill chart Decimal equivalent chart

Common questions

What is a 11.5 mm drill in decimal and mm?: 0.4528 in, or 11.500 mm; nearest fractional drill: 29/64" (0.4531 in, +0.0004 in); nearest number / letter drill: Letter Z (0.4130 in, -0.0398 in).
What RPM for a 11.5 mm drill in steel?: In low-carbon steel (1018) an HSS 11.5 mm drill (0.4528 in) runs about 760 RPM at 90 SFM; a carbide drill about 2,530 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 11.5 mm drill?: About 0.0101 in/rev in mild steel, 0.0094 in/rev in aluminum and 0.0076 in/rev in 304 stainless. At 760 RPM that is 7.68 IPM in steel (IPM = RPM × IPR).
What RPM for a 11.5 mm drill in aluminum?: 2,110 RPM with HSS (250 SFM) or up to 5,060 RPM with carbide (600 SFM), feeding about 0.0094 in/rev.
What size is a 11.5 mm drill?: 0.4528 in / 11.50 mm. The nearest other drills are 29/64" (0.4531 in), 11.6 mm (0.4567 in), 11.4 mm (0.4488 in).

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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