McMaster-Carr logo
    Filter by
    System of Measurement
    Thread Pitch
    Industrial Info Snippet
    Attribute Image
    Fastener Strength Grade/Class
    Industrial Info Compare
    Specifications Met
    Hex Nut Profile
    Material
    Width
    Attribute Image
    Thread Type
    Thread Fit
    Industrial Info Snippet
    Attribute Image
    Fastener Strength Rating
    DFARS Specialty Metals
    Industrial Info Compare
    Thread Direction
    Thread Spacing
    Industrial Info Compare
    Sold As
    U.S.–Mexico–Canada Agreement (USMCA) Qualifying
    Export Control Classification Number (ECCN)
    Industrial Info Snippet
    Drive Style
    Industrial Info Snippet
    Insert Maximum Temperature
    Forward
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Print
    How can we improve?
    Comments
    E-mail address (if you would like a response)
    7 Products

    Locking Type

    Locking Type

    Performance

    Nylon-Insert Locknuts

    Versatile yet economical, these are the most commonly used locknuts. 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.
    High-Strength Steel
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    Rated Grade 8, Grade C, or Class 10, these locknuts are about 25% stronger than medium-strength steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Thread
    Size
    Wd.,
    mm
    Ht.,
    mm
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp., ° F
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    M36 × 3 mm5536Class 10
    		185DIN 985, ISO 10511194645A125000000
    M36 × 4 mm5536Class 10
    		185DIN 985194645A35000000
     
    Medium-Strength Steel
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    These Grade 5 or Class 8 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Thread
    Size
    Wd.,
    mm
    Ht.,
    mm
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp., ° F
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    M36 × 3 mm5536Class 8
    		185DIN 985, ISO 10511190576A452000000
    M36 × 4 mm5536Class 8
    		185DIN 985, ISO 10511190576A16400000
     

    Top-Lock Distorted-Thread Locknuts

    Image of Product. Front orientation. Locknuts. Top-Lock Distorted-Thread Locknuts.
    Irregularly shaped threads at the top of these locknuts grip the screw for a stronger hold than nylon-insert locknuts. Although the threads prevent the nut from backing out due to vibration, they also increase the effort to install and remove. To get these nuts off, you may need special tools, such as an impact wrench or propane torch. Nuts are not reusable.
    Medium-Strength Steel
    These Grade 5 or Class 8 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Yellow-Chromate-Plated Steel—With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.
    Thread
    Size
    Wd.,
    mm
    Ht.,
    mm
    Fastener Strength
    Grade/Class
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    M36 × 4 mm5536Class 8
    		DIN 980V193795A321000000
     

    Locknuts for use with Cotter Pins

    Use these locknuts to secure rotating parts subjected to mild vibration, such as the wheels on carts and hand trucks. They’re not recommended for use on parts exposed to high vibration because the pin can shear under prolonged stress. These nuts are reusable, but you'll need a new cotter pin (not included) with each use.
    Medium-Strength Steel
    Image of ProductInUse. Front orientation. Locknuts. Locknuts for use with Cotter Pins.
    Image of Product. Front orientation. Locknuts. Locknuts for use with Cotter Pins.
    These Grade 5 or Class 8 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.,
    mm
    Ht.,
    mm
    Fastener Strength
    Grade/Class
    For Cotter
    Pin Dia., mm
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    Steel
    M36 × 3 mm5538Class 8
    		6.3DIN 935193760A134000000
    M36 × 4 mm5538Class 8
    		6.3DIN 935193760A12200000
     
    back to top