McMaster-Carr logo
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Comments
    E-mail address (if you would like a response)
    17 Products

    Mil. Spec. Nylon-Insert Locknuts
    3D CAD models available

    These locknuts are manufactured and tested to strict U.S. military standards for material and construction. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.
    Low-Strength Steel
    Image of Product. Front orientation. Locknuts. Mil. Spec. Nylon-Insert Locknuts.
    Rated Grade 2, Class 6, or lower, these locknuts are about half as strong as medium-strength steel nuts. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Cadmium Yellow-Chromate-Plated Steel—These locknuts have good lubricity to thread on smoothly and ease installation. The plating also creates a barrier against rust that's comparable to zinc yellow-chromate plating.
    Thread
    Size
    Wd.
    Ht.
    Mil. Specs.
    Met
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Cadmium Yellow-Chromate-Plated Steel
    4-40
    1/4"5/32"MS21044-N042501000000000000000
    6-32
    5/16"3/16"MS21044-N06250100000000000000
    8-32
    11/32"9/32"MS21044-N08250100000000000000
    10-32
    3/8"9/32"MS21044-N3250100000000000000
    1/4"-28
    7/16"23/64"MS21044-N4250100000000000000
    5/16"-24
    1/2"23/64"MS21044-N5250500000000000000
    3/8"-24
    9/16"15/32"MS21044-N6250500000000000000
    1/2"-20
    3/4"19/32"MS21044-N825050000000000000
    5/8"-18
    15/16"3/4"MS21044-N1025010000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Locknuts. Mil. Spec. Nylon-Insert Locknuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Thread
    Size
    Wd.
    Ht.
    Mil. Specs. Met
    Insert Max.
    Temp., ° F
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    2-56
    1/4"9/64"MS17830-02C, MS21044C02250NASM17830, NASM21044100000000000000
    4-40
    1/4"5/32"MS21044C04250NASM210441000000000000000
    6-32
    5/16"3/16"MS21044C06250NASM21044100000000000000
    8-32
    11/32"9/32"MS21044C08250NASM210441000000000000000
    10-32
    3/8"9/32"MS21044C3250NASM210441000000000000000
    1/4"-28
    7/16"23/64"MS21044C4250NASM21044500000000000000
    3/8"-24
    9/16"15/32"MS17830-6F, MS21044C6250NASM17830, NASM2104410000000000000
    7/16"-20
    11/16"15/32"MS17830-7F, MS21044C7250NASM17830, NASM21044100000000000000
     
    back to top