Offshore

Tappex UK is able to supply two families of threaded inserts, both self-tapping, that can be used for a wide variety of applications found in the marine industry.

The first family of threaded inserts is the Tappex Trisert-3 which is available in two grades of stainless steel - 303 (A1) and 316 (A4) - both of which are passivated as standard. The Trisert-3 employs three cutting facets that provide balanced cutting forces to ensure a consistent, robust installation process. The reduced head design offers an increased bearing surface over which the application torque may be spread whilst helping to ensure the correct orientation.

Recently 6270M6-316 and 6270M10B-316 were specified for racing yachts competing in the Volvo ‘round the world’ series. In addition to its corrosion resistant properties this blind variant was chosen to eliminate the chance of swarf becoming trapped in the internal thread. For this application the product can be installed by hand or with a tapping head into filament wound glass fibre using the Tappex Production Driver.

The second family of products is Tappex Foamserts, which are made from brass (in itself having some reduced corrosion performance) with a coarse, external truncated thread form and internal thread (either Metric M2.5 to 8mm or Unified Standards are available).

Typical applications include medium and high-density foams, woods and some laminated polymer constructions. This makes them suitable for the internal furniture and decor of sailing boats and pleasure crafts.

During the installation process the cutting action of self-tapping inserts results in slight outward stress. Tappex says this is reduced to an absolute minimum with the Foamsert and enables the insert to be used where there are thin walls. The balanced cutting load of the Foamsert also reduces side thrust caused by predominantly only one cutting edge. This has the effect of guaranteeing much closer axial alignment of the insert in the hole.