McMaster-Carr logo
    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)
    90 Products

    Coupling Nuts
    3D CAD models available

    Also known as extension nuts, these are commonly used to connect lengths of threaded rod and join threaded parts.
    Low-Strength Steel
    Image of Product. Front orientation. Coupling Nuts. Coupling Nuts.
    Rated Grade 2 or lower, these are about half as strong as medium-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Black-Oxide Steel—A dark, matte coating creates a finished look. Nuts offer minimal corrosion resistance, so they're best for dry environments.
    Each
    Thread Size
    Lg.,
    mm
    Wd.,
    mm
    Threading
    Specs.
    Met
    1-9
    10-Up
    Zinc-Plated Steel
    M4 × 0.7 mm127Fully ThreadedDIN 63340000000000000000000
    M5 × 0.8 mm158Fully ThreadedDIN 633400000000000000000
    M6 × 1 mm1810Fully ThreadedDIN 633400000000000000000
    M8 × 1.25 mm2413Fully ThreadedDIN 633400000000000000000
    M10 × 1.5 mm3017Fully ThreadedDIN 633400000000000000000
    M12 × 1.75 mm3619Fully ThreadedDIN 633400000000000000000
    M14 × 2 mm4222Fully ThreadedDIN 633400000000000000000
    M16 × 2 mm4824Fully ThreadedDIN 633400000000000000000
    M18 × 2.5 mm5427Fully ThreadedDIN 63340000000000000000000
    M20 × 2.5 mm6030Fully ThreadedDIN 633400000000000000000
    M22 × 2.5 mm6632Fully ThreadedDIN 63340000000000000000000
    M24 × 3 mm7236Fully ThreadedDIN 63340000000000000000000
    M27 × 3 mm8141Fully ThreadedDIN 63340000000000000000000
    M30 × 3.5 mm9046Fully ThreadedDIN 63340000000000000000000
    M36 × 4 mm10855Fully ThreadedDIN 633400000000000000000000
     
    Black-Oxide Steel
    M18 × 2.5 mm5427Fully ThreadedDIN 63340000000000000000000
    M22 × 2.5 mm6632Fully ThreadedDIN 63340000000000000000000
    M27 × 3 mm8141Fully ThreadedDIN 63340000000000000000000
    M30 × 3.5 mm9046Fully ThreadedDIN 63340000000000000000000
    M36 × 4 mm10855Fully ThreadedDIN 633400000000000000000000
     
    Medium-Strength Steel
    Image of Product. Front orientation. Coupling Nuts. Coupling Nuts.
    These Grade 5 or Class 8 nuts are about twice as strong as low-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Black-Oxide Steel—A dark, matte coating creates a finished look. Nuts offer minimal corrosion resistance, so they're best for dry environments.
    Each
    Thread Size
    Lg.,
    mm
    Wd.,
    mm
    Fastener Strength
    Grade/Class
    Threading
    Specs. Met
    1-9
    10-Up
    Zinc-Plated Steel
    M5 × 0.8 mm158ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 6334000000000000000000000
    M6 × 1 mm1810ISO Class 8
    		Fully ThreadedDIN 633400000000000000000
    M8 × 1.25 mm2413ISO Class 8
    		Fully ThreadedDIN 633400000000000000000
    M10 × 1.5 mm3017ISO Class 8
    		Fully ThreadedDIN 633400000000000000000
    M12 × 1.75 mm3619ISO Class 8
    		Fully ThreadedDIN 633400000000000000000
    M14 × 2 mm4222ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M16 × 2 mm4824ISO Class 8
    		Fully ThreadedDIN 633400000000000000000
    M18 × 2.5 mm5427ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M20 × 2.5 mm6030ISO Class 8
    		Fully ThreadedDIN 633400000000000000000
    M22 × 2.5 mm6632ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M24 × 3 mm7236ISO Class 8
    		Fully ThreadedDIN 63340000000000000000000
    M30 × 3.5 mm9046ISO Class 8
    		Fully ThreadedDIN 63340000000000000000000
     
    Black-Oxide Steel
    M5 × 0.8 mm158ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 6334000000000000000000
    M6 × 1 mm1810ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M8 × 1.25 mm2413ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M10 × 1.5 mm3017ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M12 × 1.75 mm3619ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M14 × 2 mm4222ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M16 × 2 mm4824ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M18 × 2.5 mm5427ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M20 × 2.5 mm6030ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M24 × 3 mm7236ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M30 × 3.5 mm9046ISO Class 8
    		Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
     
    High-Strength Steel
    Image of Product. Front orientation. Coupling Nuts. Coupling Nuts.
    Rated Grade 8 or Class 10, these are about 25% stronger than medium-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Each
    Thread Size
    Lg.,
    mm
    Wd.,
    mm
    Fastener Strength
    Grade/Class
    Threading
    Specs.
    Met
    1-9
    10-Up
    Zinc-Plated Steel
    M6 × 1 mm1810ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M8 × 1.25 mm2413ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M10 × 1.5 mm3017ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M12 × 1.75 mm3619ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M16 × 2 mm4824ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M20 × 2.5 mm6030ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M24 × 3 mm7236ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M27 × 3 mm8141ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M30 × 3.5 mm9046ISO Class 10
    		Fully ThreadedDIN 633400000000000000000000
     
    Steel
    M8 × 1.25 mm2413ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M10 × 1.5 mm3017ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M12 × 1.75 mm3619ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M16 × 2 mm4824ISO Class 10
    		Fully ThreadedDIN 633400000000000000000
    M20 × 2.5 mm6030ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M24 × 3 mm7236ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M30 × 3.5 mm9046ISO Class 10
    		Fully ThreadedDIN 63340000000000000000000
    M36 × 4 mm10855ISO Class 10
    		Fully ThreadedDIN 6334000000000000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Coupling Nuts. Coupling Nuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to the harsh chemicals that 316 stainless steel can.
    Super-Corrosion-Resistant 316 Stainless Steel—The most corrosion-resistant stainless steel coupling nuts we offer, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Each
    Thread Size
    Lg.,
    mm
    Wd.,
    mm
    Threading
    Specs. Met
    1-9
    10-Up
    18-8 Stainless Steel
    M5 × 0.8 mm158Fully ThreadedDIN 63340000000000000000000
    M6 × 1 mm1810Fully ThreadedDIN 633400000000000000000
    M8 × 1.25 mm2413Fully ThreadedDIN 633400000000000000000
    M10 × 1.5 mm3017Fully ThreadedDIN 633400000000000000000
    M12 × 1.75 mm3619Fully ThreadedDIN 633400000000000000000
    M14 × 2 mm4222Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M16 × 2 mm4824Fully ThreadedDIN 63340000000000000000000
    M18 × 2.5 mm5427Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M20 × 2.5 mm6030Fully ThreadedDIN 63340000000000000000000
    M22 × 2.5 mm6632Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M24 × 3 mm7236Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M30 × 3.5 mm9046Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M33 × 3.5 mm9950Fully ThreadedDIN 633400000000000000000000
    M36 × 4 mm10855Fully ThreadedDIN 6334000000000000000000000
     
    Black-Oxide 18-8 Stainless Steel
    M5 × 0.8 mm158Fully ThreadedASME B18.2.2, DIN 633400000000000000000
    M6 × 1 mm1810Fully ThreadedASME B18.2.2, DIN 633400000000000000000
    M8 × 1.25 mm2413Fully ThreadedASME B18.2.2, DIN 6334000000000000000000
    M10 × 1.5 mm3017Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M12 × 1.75 mm3619Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
    M14 × 2 mm4222Fully ThreadedASME B18.2.2, DIN 63340000000000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    M5 × 0.8 mm158Fully ThreadedDIN 633400000000000000000
    M6 × 1 mm1810Fully ThreadedDIN 633400000000000000000
    M8 × 1.25 mm2413Fully ThreadedDIN 633400000000000000000
    M10 × 1.5 mm3017Fully ThreadedDIN 633400000000000000000
    M12 × 1.75 mm3619Fully ThreadedDIN 633400000000000000000
    M14 × 2 mm4222Fully ThreadedDIN 63340000000000000000000
    M16 × 2 mm4824Fully ThreadedDIN 63340000000000000000000
    M18 × 2.5 mm5427Fully ThreadedDIN 63340000000000000000000
    M20 × 2.5 mm6030Fully ThreadedDIN 63340000000000000000000
    M24 × 3 mm7236Fully ThreadedDIN 63340000000000000000000
     
    back to top