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Direct screw-fittings


Robust with a long service life: EJOT DELTA PT® screws for plastics create strong connections for lightweight construction.

Product image of an EJOT DELTA PT® screw

For reliable direct fastenings

The reliable direct fastener for plastics: EJOT DELTA PT® the self-tapping screw

Direct fasteners for plastics make thin-wall and flat designs possible. They offer material savings and shorter cycles for injection moulding. EJOT DELTA PT® screws also have a positive effect on overall connection costs: Direct fastening effectively reduces costs.

Plus factors

Advantages EJOT DELTA PT®

  • Minimum radial stress

    Small flank angles reduce radial stress and enable a thin-wall design.

  • High self-locking capacity in the thread

    Optimized thread pitch effectively prevents self-loosening of the screw.

  • High tensile strength and torsion strength

    The enlarged core cross section improves strength. Even in highly reinforced thermoplastics the fastener achieves high preload forces and tightening torques.

  • Cost-effective and a long service life

    Use company-standard parts, like the EJOT DELTA PT®, to reduce your warehousing costs. Thanks to the best material selection with PT10 Q&T steel the screw has an extremely long service life.

  • Secure hold

    The optimized material outflow at assembly ensures that the screw is perfectly seated.

  • Reduced weight

    In lightweight construction every gram is relevant. Unlike conventional joints, it is possible to use very short screws and small diameters.

Method and principle

They are particularly suitable for thermoplastic materials

EJOT DELTA PT® is the further development of the PT screw and the result of many years of practical experience with fastening thermoplastics. As a robust connection it guarantees top performance even under extreme implementation conditions.

Its special thread geometry is the result of thorough analysis of material displacement when forming thread. It ensures an optimal outflow of the deformed plastic material and ultimately a reliable and secure connection. The special variant EJOT DELTA PT P® is made of a high performance plastic (and is therefore suitable for lightweight and electrically or thermally insulating threaded screw connections in standard thermoplastics). The special variant EJOT DELTA PT DS has been specially developed for thermosetting plastics, which make special demands on the direct screw connection due to their hardness and brittleness.

Image of the three product variants of the EJOT DELTA PT®
EJOT DELTA PT® the three product variants
Functionality of the EJOT DELTA PT®

EJOT DELTA PT® geometry

  • Core cross section of the EJOT DELTA PT® screw

    Core cross section of the EJOT DELTA PT®

    High tensile strength and torsion strength due to large core cross section.

  • Thread flanks of the EJOT DELTA PT® screw with formed nut material

    • Optimal outflow of the deformed plastic
    • High self-locking to prevent loosening
    • High thread overlap even at short length of thread engagement
    • Extensive low-damage material outflow
  • Thread flanks of the EJOT DELTA PT® screw in detail

    • Appropriate thread geometry for plastics
    • Balanced ratio of preload force to surface pressure
    • High preload forces and tightening torques are possible
    • High self-locking by means of appropriate thread pitch for plastics
    • Large flank overlap enables low surface pressure (PFL). As a result, stress reduction in the polymer remains low and the residual preload force of the joint is maximized.
  • Cross section of the thread flank geometry of the EJOT DELTA PT® screw

    • Minimal radial expansion through 20°/30° flank angle
    • The 140° transition angle from the thread tooth to the core diameter results in a high bending stiffness in the thread tooth.
    • Thin-wall tube design possible. This means you save material and effectuate the lightweight construction aspects. Fewer injection moulding cycles are an additional process optimization.

Find the right solution for your application

EJOT DELTA PT® product types

  • for thermoplastics

    EJOT DELTA PT® for thermoplastics

    The design of the screw-in tube in conjunction with the clamping part has a decisive influence on the durability of the screw connection. The EJOT DELTA PT® has been specifically developed for direct fastening of thermoplastics.
    The combination of special thread pitch and formed flank angle enables a particularly efficient connection.

  • for thermoset plastics

    EJOT DELTA PT® DS for thermoset plastics

    The EJOT DELTA PT(R) screw enables reliable connections for plastic direct fastening. Some constructions require thermosetting plastics which, due to their hardness and brittleness, impose special requirements on direct fastening.
    Modified thread flanks are required to enable direct fastening into these particularly demanding materials. The EJOT DELTA PT® DS screw has special grooves on the proven EJOT DELTA PT® thread geometry that significantly support the cutting process in the nut thread.

  • for standard thermoplastics

    EJOT DELTA PT® P for standard thermoplastics

    When designing components for direct fastening of thermoplastics with steel screws, frequently the situation arises that the strength of the workpiece material is significantly lower than the strength of the screw material. This is particularly the case with standard thermoplastics.
    Consequently, the EJOT DELTA PT® P screw is made with the same high-performance plastic PPA GF50 as the screw material. This enables a self-tapping fastening in standard thermoplastics. Thus a lightweight and electrically or thermally insulating threaded connection can be realised.

Information and more


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