McMaster-Carr logo
    Filter by
    System of Measurement
    Threaded Insert Type
    End Type
    Key-Locking Insert Wall Type
    Number of Locking Keys
    For Tap Type
    DFARS Specialty Metals
    Industrial Info Compare
    Thread Direction
    Export Control Classification Number (ECCN)
    Industrial Info Snippet
    Profile
    U.S.–Mexico–Canada Agreement (USMCA) Qualifying
    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)
    120 Products
    About Threaded Inserts
    industrial info icon

    Choose the right threaded insert for your application and learn how to install it securely.

    Mil.-Spec. Key-Locking Threaded Inserts For Soft Metal

    Image of Product. Bottom orientation. Threaded Inserts. Mil.-Spec. Key-Locking Threaded Inserts For Soft Metal.
    These inserts are manufactured and tested to meet or compare to strict standards adopted by the U.S. military. The keys drive into aluminum and other soft metal for a secure hold that won't slip or rotate, even in vibrating vehicle or aerospace parts. These inserts are comparable to Keensert inserts.
    To install, drill and tap a hole in your material. Then, thread the insert onto the installation tool and screw it into the hole. Place the tool over the keys and hit it with a hammer to drive them in.
    Standard Wall—Stronger than thin-wall inserts, these are your go-to choice for threading most holes.
    Thin Wall—Use these inserts near the edge of workpieces or wherever you only have space for a small hole. They're also lighter than standard and extra-thick wall inserts for applications with strict weight limitations.
    Extra-Thick Wall—Stronger than standard- and thin-wall inserts, use them to reduce the size of tapped holes or replace threads that have been drilled out.
    High-Strength Cadmium-Plated Alloy Steel—These inserts have the strength to stand up to high-pressure applications and a plating that helps screws thread in smoothly.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these inserts resist rust and mild chemicals.
    Inserts
    Installation
    Tools
    Thread
    Size
    For Tap Thread
    Size
    Installed
    Lg.
    Drill Bit
    Size
    For Max.
    Hole Dia.
    No. of Locking
    Keys
    Specs. Met
    Each
    Each
    Standard Wall
     
    High-Strength Cadmium-Plated Alloy Steel
    8-32
    		5/16"-18
    		0.313"I
    		0.272"2NAS1395-0895101A1240000093904A505000000
    10-24
    		3/8"-16
    		0.313"Q
    		0.332"2MS51831A10195101A125000093904A51500000
    1/4"-20
    		7/16"-14
    		0.375"X
    		0.397"2MS51831A10295101A1050000093904A52500000
    5/16"-18
    		1/2"-13
    		0.438"29/64"
    		0.453"4MS51831A10395101A1060000093904A53500000
    3/8"-16
    		9/16"-12
    		0.500"33/64"
    		0.516"4MS51831A10495101A1070000093904A54500000
    7/16"-14
    		5/8"-11
    		0.625"37/64"
    		0.578"4MS51831A10595101A1280000093904A73900000
    1/2"-13
    		11/16"-11
    		0.688"41/64"
    		0.641"4MS51831A10695101A1310000093904A55500000
    5/8"-11
    		7/8"-14
    		0.875"53/64"
    		0.828"4MS51831A10895101A1340000093904A74600000
    3/4"-10
    		1 1/8"-12
    		1.125"1 1/16"
    		1.062"4MS51831A10995101A1360000093904A748000000
    7/8"-9
    		1 1/4"-12
    		1.250"1 3/16"
    		1.187"4MS51831A11095101A1380000093904A751000000
    1"-8
    		1 3/8"-12
    		1.375"1 5/16"
    		1.312"4MS51831A11195101A1390000093904A753000000
     
    18-8 Stainless Steel
    8-32
    		5/16"-18
    		0.313"17/64"
    		0.276"2NAS1395C0893904A500000093904A50500000
    10-24
    		3/8"-16
    		0.313"Q
    		0.336"2MS51831-10193904A510000093904A51500000
    1/4"-20
    		7/16"-14
    		0.375"X
    		0.401"2MS51831-10293904A520000093904A52500000
    5/16"-18
    		1/2"-13
    		0.438"29/64"
    		0.457"4MS51831-10393904A530000093904A53500000
    3/8"-16
    		9/16"-12
    		0.500"33/64"
    		0.521"4MS51831-10493904A540000093904A54500000
    7/16"-14
    		5/8"-11
    		0.625"37/64"
    		0.583"4MS51831-10593904A226000093904A73900000
    1/2"-13
    		11/16"-11
    		0.688"41/64"
    		0.646"4MS51831-10693904A5500000093904A55500000
    9/16"-12
    		13/16"-16
    		0.813"49/64"
    		0.771"4MS51831-10793904A2340000093904A74400000
    5/8"-11
    		7/8"-14
    		0.875"53/64"
    		0.833"4MS51831-10893904A2380000093904A74600000
    3/4"-10
    		1 1/8"-12
    		1.125"1 1/16"
    		1.067"4MS51831-10993904A2440000093904A748000000
    7/8"-9
    		1 1/4"-12
    		1.250"1 3/16"
    		1.192"4MS51831-11093904A2470000093904A751000000
    1"-8
    		1 3/8"-12
    		1.375"1 5/16"
    		1.317"4MS51831-11193904A2520000093904A753000000
     
    Thin Wall
     
    High-Strength Cadmium-Plated Alloy Steel
    2-56
    		8-32
    		0.125"29 Ga.
    		0.137"2MS51830A10195101A108000093904A15000000
    4-40
    		10-32
    		0.188"20 Ga.
    		0.164"2MS51830A10295101A1010000093904A25000000
    6-32
    		12-28
    		0.188"3/16"
    		0.190"2MS51830A10395101A1020000093904A35000000
    8-32
    		1/4"-28
    		0.250"1 Ga.
    		0.231"2MS51830A10495101A1030000093904A45000000
    10-24
    		5/16"-18
    		0.313"I
    		0.272"2MS51830A10595101A109000093904A60500000
    1/4"-20
    		3/8"-16
    		0.375"Q
    		0.332"2MS51830A10695101A112000093904A61500000
    5/16"-18
    		7/16"-14
    		0.438"X
    		0.397"4MS51830A10795101A115000093904A62500000
    3/8"-16
    		1/2"-13
    		0.500"29/64"
    		0.453"4MS51830A10895101A117000093904A63500000
    7/16"-14
    		9/16"-12
    		0.563"33/64"
    		0.516"4MS51830A10995101A119000093904A72500000
    1/2"-13
    		5/8"-11
    		0.625"37/64"
    		0.578"4MS51830A11095101A122000093904A64500000
     
    18-8 Stainless Steel
    2-56
    		8-32
    		0.125"29 Ga.
    		0.137"2MS51830-10193904A100000093904A15000000
    4-40
    		10-32
    		0.172"20 Ga.
    		0.164"2MS51830-10293904A200000093904A25000000
    6-32
    		12-28
    		0.172"3/16"
    		0.190"2MS51830-10393904A300000093904A35000000
    6-32
    		1/4"-20
    		0.250"7/32"
    		0.216"2NAS1395C0693904A212000093904A25700000
    8-32
    		1/4"-20
    		0.250"7/32"
    		0.216"2NAS1394C0893904A213000093904A25700000
    8-32
    		1/4"-28
    		0.219"15/64"
    		0.231"2MS51830-10493904A400000093904A45000000
    10-24
    		5/16"-18
    		0.313"I
    		0.276"2MS51830-10593904A600000093904A60500000
    1/4"-20
    		3/8"-16
    		0.375"Q
    		0.336"2MS51830-10693904A610000093904A61500000
    5/16"-18
    		7/16"-14
    		0.438"X
    		0.401"4MS51830-10793904A620000093904A62500000
    3/8"-16
    		1/2"-13
    		0.500"29/64"
    		0.457"4MS51830-10893904A630000093904A63500000
    7/16"-14
    		9/16"-12
    		0.563"33/64"
    		0.521"4MS51830-10993904A227000093904A72500000
    1/2"-13
    		5/8"-11
    		0.625"37/64"
    		0.583"4MS51830-11093904A6400000093904A64500000
     
    Extra-Thick Wall
     
    High-Strength Cadmium-Plated Alloy Steel
    3/8"-16
    		5/8"-11
    		0.500"37/64"
    		0.578"4MS51832A10495101A1410000093904A76200000
    1/2"-13
    		13/16"-16
    		0.688"49/64"
    		0.766"4MS51832A10695101A1420000093904A76600000
    5/8"-11
    		1"-12
    		0.875"15/16"
    		0.937"4MS51832A10895101A14300000093904A77100000
     
    18-8 Stainless Steel
    10-24
    		7/16"-14
    		0.313"X
    		0.401"2MS51832-10193904A2180000093904A75600000
    5/16"-18
    		9/16"-12
    		0.438"33/64"
    		0.521"4MS51832-10393904A2220000093904A26200000
    3/8"-16
    		5/8"-11
    		0.500"37/64"
    		0.583"4MS51832-10493904A2240000093904A76200000
    7/16"-14
    		11/16"-11
    		0.625"41/64"
    		0.646"4MS51832-10593904A2280000093904A27100000
    1/2"-13
    		13/16"-16
    		0.688"49/64"
    		0.771"4MS51832-10693904A2310000093904A76600000
    9/16"-12
    		7/8"-14
    		0.813"53/64"
    		0.833"4MS51832-10793904A2350000093904A27900000
    5/8"-11
    		1"-12
    		0.875"15/16"
    		0.942"4MS51832-10893904A2390000093904A77100000
    3/4"-10
    		1 1/4"-12
    		1.125"1 3/16"
    		1.192"4MS51832-10993904A2430000093904A77300000
    7/8"-9
    		1 3/8"-12
    		1.250"1 5/16"
    		1.317"4MS51832-11093904A2480000093904A77500000
    1"-8
    		1 1/2"-12
    		1.375"1 7/16"
    		1.442"4MS51832-11193904A2530000093904A77700000
     

    Key-Locking Threaded Inserts for Soft Metal

    Image of Product. Bottom orientation. Threaded Inserts. Key-Locking Threaded Inserts for Soft Metal.
    Add strong threads in soft metal, such as aluminum. The keys on these inserts drive into holes to hold more securely than thread-locking or helical inserts. They prevent slipping and rotating, so they’re stable enough for use in vehicle or aerospace parts that experience heavy vibration. These inserts are comparable to Keensert inserts.
    To install, drill and tap a hole in your material. Then, thread the insert onto the installation tool and screw it into the hole. Place the tool over the keys and hit it with a hammer to drive them in.
    Standard Wall—Stronger than thin-wall inserts, these are your go-to choice for threading most holes.
    Thin Wall—Use these inserts near the edge of workpieces or wherever you only have space for a small hole. They're also lighter than standard and extra-thick wall inserts for applications with strict weight limitations.
    High-Strength High-Temperature A286 Stainless Steel—High temperatures won't reduce the load capacity of these inserts. They also resist chemicals such as bleach and chlorine.
    Inserts
    Installation
    Tools
    Thread
    Size
    For Tap Thread
    Size
    Installed
    Lg.
    Drill Bit
    Size
    For Max.
    Hole Dia.
    No. of Locking
    Keys
    Specs. Met
    Each
    Each
    Standard Wall
     
    High-Strength High-Temperature A286 Stainless Steel
    1/4"-20
    		7/16"-14
    		0.375"X
    		0.397"2MS51831CA10293509A26000000093904A525000000
    3/8"-16
    		9/16"-12
    		0.500"33/64"
    		0.516"4MS51831CA10493509A2900000093904A54500000
     
    Thin Wall
     
    High-Strength High-Temperature A286 Stainless Steel
    2-56
    		8-32
    		0.125"30 Ga.
    		0.134"2MS51830CA10193509A1100000093904A15000000
    4-40
    		10-32
    		0.172"20 Ga.
    		0.161"2MS51830CA10293509A1200000093904A25000000
    6-32
    		12-28
    		0.172"3/16"
    		0.187"2MS51830CA10393509A1300000093904A35000000
    8-32
    		1/4"-28
    		0.219"1 Ga.
    		0.228"2MS51830CA10493509A1400000093904A45000000
    10-24
    		5/16"-18
    		0.313"I
    		0.272"2MS51830CA10593509A1500000093904A60500000
    1/4"-20
    		3/8"-16
    		0.375"Q
    		0.332"2MS51830CA10693509A1600000093904A61500000
    3/8"-16
    		1/2"-13
    		0.500"29/64"
    		0.453"4MS51830CA10893509A1900000093904A63500000
    1/2"-13
    		5/8"-11
    		0.625"37/64"
    		0.578"4MS51830CA11093509A2200000093904A64500000
     

    Mil. Spec. Rivet-Mount Nuts

    Image of ProductInUse. Front orientation. Contains Annotated. Rivet-Mount Nuts.
    Image of Product. Front orientation. Rivet-Mount Nuts.
    Image of Attribute. Front orientation. Contains Annotated.
    Image of Attribute. Top orientation. Contains Annotated.
    Create threads in hard-to-work areas—where you can’t reach the back of a workpiece, or material is too thin to be tapped. For a strong grip, these rivet-mount nuts have distorted threads that increase friction with bolts. Because they mount with two rivets, they won’t spin when you’re tightening screws. However, these nuts do move inside their retainers, which lets you install bolts at a slight angle; use them to align with off-center parts. All meet military guidelines for dimensions and material.
    A286 Stainless Steel—A286 stainless steel nuts are corrosion resistant.
    Cadmium-Plated Carbon Steel and Cadmium-Plated Steel—Cadmium-plated nuts resist corrosion in industrial and saltwater environments, although will lose their corrosion resistance over 450° F. The cadmium plating also adds lubricity, making these nuts easy to install.
    Silver-Plated A286 Stainless Steel—Silver-plated stainless steel nuts withstand temperatures up to 800° F. The silver plating also adds lubricity and prevents seizing caused by friction between nuts and bolts.
    Lubricated—Lubricated nuts thread onto bolts smoothly.
    Base
    Barrel
    Mounting
    Thread
    Size
    Lg.
    Wd.
    Thk.
    Dia.
    Ht.
    No. of
    Holes
    Hole
    Dia.
    Hole
    Ctr.-to-Ctr.
    Mil. Spec.
    Each
    Steel—Unlubricated
    4-40
    		21/32"5/16"3/32"1/8"1/16"20.098"13/32"MS21075-04N90857A12600000
    6-32
    		11/16"11/32"3/32"0.172"5/64"20.098"7/16"MS21075-06N90857A1270000
    8-32
    		45/64"23/64"3/32"0.203"5/32"20.098"15/32"MS21075-08N90857A1280000
     
    Cadmium-Plated Steel—Lubricated
    4-40
    		21/32"5/16"3/32"1/8"1/16"20.098"13/32"MS21075L04N90857A1310000
    6-32
    		11/16"11/32"3/32"0.172"5/64"20.098"7/16"MS21075L06N90857A1320000
    8-32
    		45/64"23/64"3/32"0.203"5/32"20.098"15/32"MS21075L08N90857A1330000
     
    Carbon Steel—Unlubricated
    6-32
    		61/64"13/32"1/32"0.172"11/64"20.098"11/16"MS21059-0690857A1010000
    8-32
    		61/64"13/32"1/32"0.203"7/32"20.098"11/16"MS21059-0890857A1020000
     
    Cadmium-Plated Carbon Steel—Lubricated
    4-40
    		61/64"13/32"1/32"0.141"9/64"20.098"11/16"MS21059L0490857A1060000
    6-32
    		61/64"13/32"1/32"0.172"11/64"20.098"11/16"MS21059L0690857A1070000
    8-32
    		61/64"13/32"1/32"0.203"7/32"20.098"11/16"MS21059L0890857A1080000
     
    A286 Stainless Steel—Lubricated
    4-40
    		21/32"5/16"3/32"1/8"1/16"20.098"13/32"MS21076L04N90857A14100000
    6-32
    		11/16"11/32"3/32"0.172"5/64"20.098"7/16"MS21076L06N90857A14200000
    6-32
    		61/64"13/32"1/32"0.172"11/64"20.098"11/16"MS21060L0690857A12000000
    8-32
    		45/64"23/64"3/32"0.203"5/32"20.098"15/32"MS21076L08N90857A1430000
    8-32
    		61/64"13/32"1/32"0.203"7/32"20.098"11/16"MS21060L0890857A1210000
     
    Silver-Plated A286 Stainless Steel—Unlubricated
    4-40
    		21/32"5/16"3/32"1/8"1/16"20.098"13/32"MS21076-04N90857A13600000
    6-32
    		61/64"13/32"1/32"0.172"11/64"20.098"11/16"MS21060-0690857A11400000
    8-32
    		45/64"23/64"3/32"0.203"5/32"20.098"15/32"MS21076-08N90857A13700000
     
    back to top