11.3 mm drill size

    A 11.3 mm metric drill is 0.4449 in (11.300 mm). It is the form (roll) tap, 65% thread drill for M12x1.5.

    Decimal inch
    0.4449
    Millimeters
    11.300
    Nearest 1/64
    7/16" (+0.0074)
    Type
    metric drill

    Nearest equivalents in other systems

    Drills closest to 11.3 mm
    SystemDrillInchmmDifference
    Fractional7/16"0.437511.112-0.0074 in
    Number / letterLetter Z0.413010.490-0.0319 in

    Speeds and feeds: in mild steel an HSS drill starts at about 770 RPM and 0.0101 in/rev (7.78 IPM); in 6061 aluminum about 2,150 RPM.

    11.3 mm drill speeds and feeds by material

    Jobber-length twist drill, D = 0.4449 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

    11.3 mm drilling speeds
    MaterialHSS SFMHSS RPMCarbide SFMCarbide RPMFeed (in/rev)HSS IPMCarbide IPM
    Aluminum (6061)2502,1506005,1500.009320.047.9
    Brass / free-machining1501,2904003,4300.00749.5525.4
    Low-carbon steel (1018)907703002,5800.01017.7826.1
    Alloy steel (4140, annealed)706002502,1500.01116.6623.9
    Stainless 304403401501,2900.00752.559.67
    Gray cast iron806902502,1500.00765.2416.3
    Titanium 6Al-4V252101008600.00470.994.04
    Plastics (acetal)3002,5805004,2900.005614.424.0

    Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 770 RPM × 0.257 mm/rev = 198 mm/min.

    Worked example: 11.3 mm drill in 1018 steel

    1. HSS drill in low-carbon steel: 90 SFM.
    2. RPM = 3.82 × 90 ÷ 0.4449 ≈ 770 RPM.
    3. Feed for a 0.445 in drill in mild steel ≈ 0.0101 in/rev.
    4. IPM = 770 × 0.0101 = 7.78 IPM.

    Peck cycle by hole depth

    11.3 mm drill: depth and canned cycle
    DepthCyclePeckNote
    3×D = 1.335 in (33.9 mm)G81 (no peck)NoneUp to 3×D a sharp drill clears chips on its own.
    5×D = 2.224 in (56.5 mm)G73 chip-break1 × DChip-break pecks; full retract if chips pack (soft aluminum, stainless).
    8×D = 3.559 in (90.4 mm)G83 full retract0.5-1 × D, shrinking with depthRetract to clear chips; reduce feed ~10-20% past 5×D.

    Taps that use a 11.3 mm drill

    • M12x1.5 — form (roll) tap, 65% thread

    Nearest drills

    • 11.2 mm: 0.4409 in / 11.200 mm (-0.0039 in)
    • 11.4 mm: 0.4488 in / 11.400 mm (+0.0039 in)
    • 7/16": 0.4375 in / 11.112 mm (-0.0074 in)
    • 11.1 mm: 0.4370 in / 11.100 mm (-0.0079 in)

    Common questions

    What is a 11.3 mm drill in decimal and mm?
    0.4449 in, or 11.300 mm; nearest fractional drill: 7/16" (0.4375 in, -0.0074 in); nearest number / letter drill: Letter Z (0.4130 in, -0.0319 in).
    What RPM for a 11.3 mm drill in steel?
    In low-carbon steel (1018) an HSS 11.3 mm drill (0.4449 in) runs about 770 RPM at 90 SFM; a carbide drill about 2,580 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
    What feed for a 11.3 mm drill?
    About 0.0101 in/rev in mild steel, 0.0093 in/rev in aluminum and 0.0075 in/rev in 304 stainless. At 770 RPM that is 7.78 IPM in steel (IPM = RPM × IPR).
    What RPM for a 11.3 mm drill in aluminum?
    2,150 RPM with HSS (250 SFM) or up to 5,150 RPM with carbide (600 SFM), feeding about 0.0093 in/rev.
    What tap uses a 11.3 mm drill?
    M12x1.5 (form (roll) tap, 65% thread).

    Nearby drill sizes

    Sources

    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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