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Trisert from Tappex Thread Inserts Lts

Trisert

The Tappex Trisert range of inserts for plastics has been developed for various environments and application criteria. It includes three primary designs – Double ended, Reduced headed and Headed, all available as Normal limit and Close limit.

Double Ended – Product Features

Three primary and three secondary equidistant cutting flutes over the length of the external form, give a more balanced cutting load than other forms of self-tapping insert. The cutting action takes place at a larger number of points on the thread form over the length and circumference of the insert.

Lead on both ends allows the insert to be installed either way up, therefore, where the volumes dictate that bowl feeding equipment is required, it is not necessary to incorporate complex flighting systems to orientate the insert, which makes bowl feeding simpler and reduces tooling costs.

Free running internal thread due to there being no interruption to the internal thread, as the external longitudinal flutes produce the cutting action during installation.

Reduced outward stress – During the installation process the cutting action of self-tapping inserts results in slight outward stress. This is reduced to an absolute minimum with the Trisert and enables the insert to be used in brittle materials and also where there are thin walls.

Improved axial alignment – The balanced cutting load of the Trisert 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.

Design Aids

  • In conjunction with the six cutting flutes, greater interference can be achieved by the special truncated thread form, increasing radial and pull out performance. The coarseness of the external thread retains a greater proportion of the predominantly weaker parent material improving the performance of the insert and allowing shorter standard lengths to be specified.
  • The Trisert is available in three standard lengths – short length for applications where space is limited, regular length, and long length for maximum pull out loading in all applications.
  • Due to the Triserts coarse thread form, the greater helix angle of the thread produces a greater resistant component of force radially, and increases the radial stripping torque of the insert. It is possible to stall torque the Trisert at the bottom of the hole increasing the locking action for applications subject to vibration.
  • With the slotted design of self-tapping insert, the accumulation of swarf at the bottom of the insert can cause contamination of the insert’s internal thread. The Trisert eliminates this problem as the majority of loose material is trapped in the cutting flutes.
  • Close limit Triserts should be specified where thin walls or thermoset materials are required and mean the interference between insert and material must be tightly controlled.

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