MSM1 Composite Fasteners

MSM1 fasteners consist of an externally threaded stud permanently attached to a thin, perforated base plate. They provide a reliable threaded attachment point on components where conventional through-bolting is either impossible or undesirable. Typical applications include composite construction, vehicle and boat building, model making, mould making and equipment construction, for example for attaching panels, brackets, fittings, supports or installed components. The fasteners can either be embedded during laminate production or subsequently bonded to the surface of a finished component using a suitable structural adhesive.

Load Transfer via the Base Plate

The main difference compared with a stud inserted directly through the component is the large-area base plate. It distributes tensile and shear loads over a larger area of the laminate or adhesive joint. The perforations in the base plate allow resin or adhesive to pass through during laminating or bonding. This provides additional mechanical integration of the base plate into the resin or adhesive layer. Depending on the version, the round base plate has a diameter of 23 or 38 mm.

Processing

Laminating in
The fastener can be positioned between or beneath reinforcement layers during laminate lay-up. Resin and reinforcement fibres should surround the base plate as uniformly as possible. Particularly with higher loads, care should be taken to ensure that the forces are not transferred solely through a thin outer laminate layer.

Subsequent bonding
Alternatively, the base plate can be bonded to a finished component using a suitable structural adhesive. The bonding surfaces must be clean, dry and free from release agents, grease and other contaminants. Smooth surfaces should be prepared in accordance with the requirements of the adhesive system being used. For larger bond gaps, a sufficiently thixotropic, gap-filling structural adhesive should be used.

Suitable Materials

Depending on the manufacturing and fastening method, suitable substrates include:

• GRP laminates
• CFRP laminates
• SMC and BMC components
• thermoset and thermoplastic materials
• sandwich components
• polymer foams
• elastomers and rubber
• other sufficiently load-bearing materials and moulded components

Selecting the Appropriate Version

The composite fasteners offered by R&G differ in thread diameter, stud length and base plate diameter. A larger base plate generally provides a larger area for load transfer. However, the actual load-bearing capacity always depends on the component design, laminate thickness and fibre orientation, the adhesive or resin system used, surface preparation and the type of load applied.

Material

Manufactured from zinc-plated mild steel.

Version Designation

Example: MSM1 B38 M6 × 30

• MS = mild steel
• M1 = externally threaded stud
• B = base plate without central through-hole
• 23 / 38 = diameter of the round base plate in mm
• M4 / M6 / M8 = thread diameter
• 20 / 30 = stud length in mm

Technical Notes

• The permissible load is not determined by the thread diameter alone. In many applications, the connection between the base plate and the laminate or bonded surface is the structurally decisive area.
• For high tensile or shear loads, the base plate should be selected as large as practicable and adequately integrated into the laminate structure.
• With sandwich components, the load introduction must be designed so that the skins and core material are not locally overloaded.
• For CFRP components exposed to moisture, the electrochemical compatibility between the carbon fibres and the metallic fastener must be taken into account. Electrical isolation may be required depending on the application.
• For safety-relevant or highly loaded connections, we recommend testing the complete joint on the intended component under realistic service conditions.