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Small Joint Assemblies

Holds reliably without screws or rivets.

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Small Joint Assembly Applications

Small joints are typically irregularly shaped with only a small area available for bonding. The smaller, more irregular the joint, the greater the challenge to create a firm hold that can withstand heavy wear. Generally these are insertion or overlap joints, or some combination of the two. They are very prominent in sporting goods, electronics, furniture, motors and electrical components.

  • 3M industrial bonding solution for sporting goods

    Mortise and tenon joints rely on the strength of the wood to help resist stress.

  • Golf club

    Shaft-hosel designs transfer the impact force of a golf club head when striking a ball.

  • A small side table with lampshade and bedside accessories.
    Furniture

    Mortise and tenon joints rely on the strength of the wood to help resist stress.

  • 3M™ Scotch-Weld™ Threadlocker TL72 being applied to ceiling fire sprinkler

    Small joints attached with threaded mechanical fasteners provide stiff, structural assemblies.

  • Application of bonding solutions to electrical parts.
    Electronics Parts Assembly

    Small joints attached with threaded mechanical fasteners provide stiff, structural assemblies.

  • Application of bonding adhesive solutions to rubber and plastic parts in small joints.
    Rubber and Plastic Parts Assembly

    Allow tight adhesion of low surface energy materials with chemical resistance for durable and strong adhesion.


Common Joint Types and Stresses in Small Joint Assemblies

    • Acrylic, epoxy and urethane adhesives
    • Over 1000 psi in overlap shear strength
    • For highest strength, fatigue and environmental resistance
    • Excellent for metal-to-metal bonds
    • One part solvent-free adhesive
    • Reaches handling strength in 5–10 seconds
    • Best for small bond lines (<10 cm²)
    • Excellent for rubbers and plastics
    • Very tight bond lines with near instant strength
    • 100% solid
    • Thermoplastic resin
    • Reaches bond strength in seconds
    • Best for wood and plastic
    • Single component
    • Hot-applied thermosetting adhesive
    • Immediate strength and holding power
    • Final cured strength over 1,000 psi
    • Best for wood and plastic
  • tube-in-shaft small joint assembly

     

  • Most small joint assemblies are 3-dimensional and are generally insertions such as mortise-and-tenon or tube-in-shaft. Because the joints are small, with forces being applied from multiple directions, the joint receives stress in nearly all forms – tension, compression, shear and cleavage. The insertion design of the joint allows the adhesive to handle the tension, compression and shear stresses while the substrates themselves help handle the cleavage.​

Peel and Shear Stress of Overlap Joints

  • Some small joint assemblies are 2-dimensional with a majority of the stress applied as shear or peel/cleavage. Unlike panel-to-frame assemblies which have relatively long lineal lengths to disperse the load, small joint assemblies require very high strength adhesives capable of handling the stresses with very little area.​​​

  • Peel and Shear Stress of Overlap Joints

Performance Factors for Small Joint Assemblies

The 3M technologies shown below are commonly used in small joint applications. Use this list as a relative comparison of product performance.

  • + = Good ++ = Better +++ = Best

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Need help finding the right product for your project? Contact us if you need product, technical or application advice or want to collaborate with a 3M technical specialist, or give us a call at 1-800-831-0658.
Need help finding the right product for your project? Contact us if you need product, technical or application advice or want to collaborate with a 3M technical specialist, or give us a call at 1-800-831-0658.