PART NUMBER:

NA2181

FEDERAL SUPPLY CODE:

32387

NA2181 Series Dome Nut

DOME NUT -- TWO-LUG, SELF-SEALING, SELF-LOCKING, FLOATING NUT ELEMENT.

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Specifications
MATERIAL:
  • NUT

    Carbon or alloy steel, A286 CRES per AMS5525 or AMS5732.

  • DOME

    Carbon steel grade C1050 per AMS5085. A286 CRES per AMS5525.

  • WASHER

    Aluminum alloy or alloy steel. A286 CRES per AMS5732.

  • SEAL -- 225 DEGREES FAHRENHEIT

    Rubber, MIL-PRF-6855, class I, grade 60, durometer 60, color black.

  • SEAL -- 350 DEGREES FAHRENHEIT

    Fluorosilicone rubber, MIL-DTL-25988, type II, class 1, durometer 70, color blue.

  • SEAL -- 450 DEGREES FAHRENHEIT

    Silicone rubber, AMS3304, durometer A70, color red.

FINISH:
  • "A" CODE

    Steel nut and dome with aluminum alloy or steel washer. Fuel resistant MIL-PRF-6855 (225 Deg. F). Steel nut, dome and washer cad plate per AMS-QQ-P-416, type II, class 2. Aluminum washer alodine per MIL-C-5541. Nut dry-film lubricant AS5272 over cad plate.

  • "S" CODE

    Steel nut, dome and washer. Fuel resistant MIL-DTL-25988 (350 Deg. F). Steel nut, dome and washer cad plate per AMS-QQ-P-416, type II, class 2. Nut dry-film lubricant per AS5272 over cad plate.

  • "X" CODE

    Same as "A" code without dry-film lubricant.

  • "Y" CODE

    Same as "S" code without dry-film lubricant.

  • "C" CODE

    A286 CRES nut, dome and washer passivate per AMS2700. Nut silver plate per AMS2410. Non-fuel resistant AMS3304 seal (450 Deg. F).

  • "F" CODE

    A286 CRES nut, dome and washer passivate per AMS2700. Nut dry-film lubricant per AS5272. Fuel resistant MIL-DTL-25988 seal (350 Deg. F).

  • "R" CODE

    A286 CRES nut, dome and washer passivate per AMS2700. Nut dry-film lubricant per AS5272. Fuel resistant MIL-PRF-6855 seal (225 Deg. F).

SERVICE TEMP.:
  • MIL-PRF-6855 RUBBER

    65 degrees Fahrenheit to 250 degrees Fahrenheit.

  • MIL-DTL-25988 FLUOROSILICONE RUBBER

    65 degrees Fahrenheit to 350 degrees Fahrenheit.

  • AMS3304 RUBBER

    65 degrees Fahrenheit to 450 degrees Fahrenheit.

VARIATIONS:
  • "K" CODE

    Add after dash no. for optional stiffening flange.

  • "N" CODE

    Add after dash no. for no stiffening flange.

  • NO CODE

    Stiffening flange at manufacturer's option.

  • "Z" CODE

    Add after dash no. for dome and washer to be coated with a galvanic reaction resistant coating per NAS4006. Shall be identified with a permanent spot, bad or patch of yellow independent #73X ink applied to top of dome.

APPLICATION:
  • The dome of this assembly prevents wire abrasion, traps metallic flakes and protects bolt threads against contamination.

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Product Information

Marketing Summary

PART #: NA2181

  • Two-Lug
  • Self-Sealing
  • Self-Locking
  • Floating Nut Element

Part Number Example Callout

NA2181 C – 02 K Z :

NA2181 = Basic Part Number
C = A286 Corrosion Resistant Steel (See Finish Section)
-02 = .1900-32 UNJF-3B Thread Size (See Table I in Engineering Specs)
K = Stiffening Flange Required (See Variations Section)
Z = Galvanic Reaction Resistant Coated Dome and Washer (See Variations Section)

Notes:

  1. Minimum radial float shall be .020. Maximum axial float shall be .030.
  2. Nut element shall be capable of engagement with a bolt in the maximum misaligned position.
  3. Pressure range is 0 to 50 PSI.

Specifications

MATERIAL
  • NUT:

    Carbon or alloy steel, A286 CRES per AMS5525 or AMS5732.

  • DOME:

    Carbon steel grade C1050 per AMS5085. A286 CRES per AMS5525.

  • WASHER:

    Aluminum alloy or alloy steel. A286 CRES per AMS5732.

  • SEAL -- 225 DEGREES FAHRENHEIT:

    Rubber, MIL-PRF-6855, class I, grade 60, durometer 60, color black.

  • SEAL -- 350 DEGREES FAHRENHEIT:

    Fluorosilicone rubber, MIL-DTL-25988, type II, class 1, durometer 70, color blue.

  • SEAL -- 450 DEGREES FAHRENHEIT:

    Silicone rubber, AMS3304, durometer A70, color red.

FINISH
  • "A" CODE:

    Steel nut and dome with aluminum alloy or steel washer. Fuel resistant MIL-PRF-6855 (225 Deg. F). Steel nut, dome and washer cad plate per AMS-QQ-P-416, type II, class 2. Aluminum washer alodine per MIL-C-5541. Nut dry-film lubricant AS5272 over cad plate.

  • "S" CODE:

    Steel nut, dome and washer. Fuel resistant MIL-DTL-25988 (350 Deg. F). Steel nut, dome and washer cad plate per AMS-QQ-P-416, type II, class 2. Nut dry-film lubricant per AS5272 over cad plate.

  • "X" CODE:

    Same as "A" code without dry-film lubricant.

  • "Y" CODE:

    Same as "S" code without dry-film lubricant.

  • "C" CODE:

    A286 CRES nut, dome and washer passivate per AMS2700. Nut silver plate per AMS2410. Non-fuel resistant AMS3304 seal (450 Deg. F).

  • "F" CODE:

    A286 CRES nut, dome and washer passivate per AMS2700. Nut dry-film lubricant per AS5272. Fuel resistant MIL-DTL-25988 seal (350 Deg. F).

  • "R" CODE:

    A286 CRES nut, dome and washer passivate per AMS2700. Nut dry-film lubricant per AS5272. Fuel resistant MIL-PRF-6855 seal (225 Deg. F).

SERVICE TEMP.
  • MIL-PRF-6855 RUBBER:

    65 degrees Fahrenheit to 250 degrees Fahrenheit.

  • MIL-DTL-25988 FLUOROSILICONE RUBBER:

    65 degrees Fahrenheit to 350 degrees Fahrenheit.

  • AMS3304 RUBBER:

    65 degrees Fahrenheit to 450 degrees Fahrenheit.

VARIATIONS
  • "K" CODE:

    Add after dash no. for optional stiffening flange.

  • "N" CODE:

    Add after dash no. for no stiffening flange.

  • NO CODE:

    Stiffening flange at manufacturer's option.

  • "Z" CODE:

    Add after dash no. for dome and washer to be coated with a galvanic reaction resistant coating per NAS4006. Shall be identified with a permanent spot, bad or patch of yellow independent #73X ink applied to top of dome.

APPLICATION
  • :

    The dome of this assembly prevents wire abrasion, traps metallic flakes and protects bolt threads against contamination.