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    Aerospace Fasteners

    Aerospace Fasteners, TorqBolt 12-point fastener with tB ligature and alloy grade marking

    Aerospace fasteners are precision-machined, fully traceable threaded fasteners produced under AS9100D Rev D quality systems for civil and military airframe, engine, and rotorcraft applications. The dominant drive geometries are external 12-point (under MS21250, NAS1351, AS3216, NAS6303-NAS6320, MIL-DTL-7838) and internal hexalobular (ISO 14579), and the dominant alloys are A286 (UNS S66286), Inconel 718 (UNS N07718), Ti-6Al-4V (Grade 5), MP35N (UNS R30035), Waspaloy, AISI 8740 chromoly, AISI 4340, 17-4 PH and H-11 tool steel, with each grade chosen against tensile target, service temperature, and corrosion environment.

    TorqBolt is an AS9100D-certified aerospace fastener manufacturer, producing 12-point bolts, hex bolts, cap screws, stud bolts, hex nuts, washers, and rivets to NAS, MS, AS, MIL, and AMS specifications. Quality systems include AS9100D + ISO 9001:2015, with NORSOK M-630 and NACE MR0175 / ISO 15156 qualifications for sour-service offshore applications. Each fastener head carries the struck tB manufacturer ligature plus the alloy grade marking, and every lot ships with a mill test report (MTC 3.1 standard, MTC 3.2 critical with third-party witness inspection).

    Capability Summary

    • Specifications: NAS, MS, AS, MIL, AMS, NASM, DIN
    • Alloys: A286, Inconel 718, Ti-6Al-4V, MP35N, Custom 465, AISI 8740 chromoly, AISI 4340, 17-4 PH, H-11 tool steel, L19
    • Geometries: 12-point, hex, internal hexalobular, socket head, button head, flat head, flange
    • Quality systems: AS9100D, ISO 9001:2015, NORSOK M-630, NACE MR0175, NACE/AMPP
    • Mill test reports: MTC 3.1 (standard) and MTC 3.2 (critical service) with every lot
    • Traceability: lot number ties bolt to heat number on raw bar stock

    Specifications We Produce

    Spec familyWhere to find it
    MS21250 (160 ksi 12-point)MS21250
    NAS1351 (close-tolerance 12-point)NAS1351
    AS3216 (180 ksi superalloy 12-point)AS3216
    NAS6303-NAS6320 tension seriesNAS6303 to NAS6320
    MIL-DTL-7838 (legacy)MIL-DTL-7838

    Material Capability

    For deep alloy datasheets see A286, Inconel 718, Ti-6Al-4V, MP35N, L19, and alloya286.com for the canonical A286 hub.

    UNJ-3A External Thread Dimensions (Common 12-Point Bolt Sizes)

    Per SAE AS8879 (controlled-root-radius UNJ external thread). 12-point aerospace bolts under MS21250, NAS1351, AS3216, NAS6303 to NAS6320 are produced to UNJ-3A external thread tolerances. Root radius 0.150 P to 0.180 P (where P = pitch) for fatigue resistance, this is the difference vs standard UN-3A and the reason aerospace specifies UNJ.

    NominalTPIPitch P (mm)Major Dia Min (mm)Major Dia Max (mm)Pitch Dia Min (mm)Pitch Dia Max (mm)Minor Dia Min (mm)Minor Dia Max (mm)
    1/4-28 UNJF-3A280.9076.2976.3505.7065.7705.1565.296
    5/16-24 UNJF-3A241.0587.8757.9387.1857.2496.5536.711
    3/8-24 UNJF-3A241.0589.4629.5258.7738.8408.1398.298
    7/16-20 UNJF-3A201.27011.05111.11310.22710.2979.4679.652
    1/2-20 UNJF-3A201.27012.63812.70011.81511.88711.05111.243
    9/16-18 UNJF-3A181.41114.22514.28813.31013.38512.46612.673
    5/8-18 UNJF-3A181.41115.81215.87514.89714.97314.05414.262
    3/4-16 UNJF-3A161.58818.99119.05017.96118.04017.01817.246
    7/8-14 UNJF-3A141.81422.16622.22521.00121.08519.92620.181
    1-12 UNJF-3A122.11725.33625.40023.97424.06422.71722.985
    1 1/4-12 UNJF-3A122.11731.68731.75030.32830.41829.07229.343
    1 1/2-12 UNJF-3A122.11738.03738.10036.67836.76835.42235.693
    1 15/16-12 UNJF-3A122.11749.14949.21347.79147.88646.53546.812
    2-12 UNJF-3A122.11750.73750.80049.37849.47348.12248.399

    Internal thread (UNJ-3B, mating nut) tolerances and metric M-J equivalents available on request. Send drawing or spec callout to info@torqbolt.com.

    What to include in your RFQ

    A useful 12-point bolt RFQ packs the engineering data into one email so we can quote in 24 working hours instead of an iteration loop. Include: (1) drawing or spec callout (NAS / MS / AS / MIL / AMS / DIN number), (2) thread size (metric M-designation or inch UNJ designation), (3) length under-head, (4) alloy preference (or "per spec"), (5) lot quantity, (6) MTC level (3.1 standard or 3.2 critical-service witness inspection), (7) need-by date, (8) end-use industry (aerospace, motorsport, diesel, marine), and (9) any coating or surface treatment requirement.

    Drawings can be 2D PDF, 3D STEP, or photograph of an existing bolt with caliper-measured dimensions. We accept all formats. For repeat-buy programs we file the drawing in the customer master and the second order quotes off the on-file drawing.

    Lead time and mill test report

    Stock alloys (A286, AISI 8740 chromoly, AISI 4340, 17-4 PH, 316 stainless) ship in 4 to 6 weeks. Specialty alloys (Inconel 718, MP35N, Custom 465, Ti-6Al-4V, L19 race-grade) take 8 to 12 weeks depending on raw-bar availability. Critical-service orders requiring MTC 3.2 third-party witness inspection (Lloyd's, DNV, ABS, BV) add 1 to 2 weeks for the witness scheduling at the customer's preferred witness body.

    Mill test report MTC 3.1 is standard at no additional cost and covers chemistry, mechanical properties (tensile, yield, elongation, hardness), microstructure note, and heat-treatment cycle. MTC 3.2 adds the third-party witness signature on every test event from raw bar inspection through final lot acceptance, and is required by most aerospace prime customers and offshore oil-gas operators for tier-1 critical-service joints.

    Request a Quote

    RFQ to info@torqbolt.com, call +91-22-66157017, or WhatsApp +91-22-66157017.

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