Self-tapping fasteners


Strong connections for lightweight construction. With EJOT DELTA PT®, the self-tapping fasteners for thermoplastic materials.


Reliable plastic threaded fasteners

EJOT DELTA PT® is a thread-forming screw for plastics and is especially suitable for thermoplastic materials.

The EJOT DELTA PT® screw is a development of the PT screw, and the result of years of hands-on experience of screw fastening in thermoplastic materials. As a rugged fastener it delivers superb performance, even under extreme conditions of use.

Method / principle

The special thread geometry, which is the result of a thorough analysis of material displacement during thread-forming, allows the formed plastic material to flow off in an optimal manner.


Self-tapping fasteners for plastics are ideal for thin-walled, flat construction methods. Their use can lead to material savings and shorter injection moulding cycle times. Taking into account the overall fastening costs for a component, self-tapping fasteners provide significant potential for savings.

Product benefits
  • Significantly longer joint life
  • Optimised material flow during screw fastening
  • Good vibration resistance
  • High tensile strength and torsional resistance
  • Made of heat-treated steel PT 10

Product benefits

There are many good reasons for using our products.

Strength and options.
Point by point.

Minimal radial stress

Small flank angles reduce radial stress, allowing for thin-walled construction methods.

Secure hold

A perfect fit, through optimised material flow during assembly.

Self-locking effect in thread

The optimised pitch minimises the possibility of the screw working loose.

Extended life

Quick to install but very durable, thanks to the use of heat-treated steel PT 10.

High tensile strength and torsional resistance

The enlarged core cross-section increases the strength of the screw so that high preload forces and tightening torques can be achieved even in high-strength thermoplastics.

Weight reduction

In lightweight construction every gram counts. In contrast to conventional joints, shorter screws and/or smaller diameters can be used.


Lower inventory costs through the use of standard parts.

Detailed description


Thread geometry

Compared to conventional thread flanks of tapping screws with a 60° flank angle, the optimised flank angle of the EJOT DELTA PT® screw reduces radial extension. The 20° or 30° angle generates only low radial extension, making thin-walled construction possible. The large axial component allows the formed plastic material to flow off in an optimal manner.

EJOT DELTA PT® – Flank geometry

Flank geometry


Good resistance to vibration

The design of the thread pitch allows for good vibration resistance, effectively preventing the screw from working loose.


Increased dynamic load capacity

The new core profiling has resulted in even greater safety under dynamic loading. The fatigue strength of the screw is substantially increased by the enlarged core cross-section and the optimised thread profile. To further increase dynamic security, the thread ridge has been stabilised at the root to reduce the risk of flank breakage. The optimised pitch, resulting in an increased thread coverage, has also reduced the risk of fatigue fracture of the thread flank.


Personalised design support


Free support. With the prognosis program Delta Calc.

You must log into the service area of the website in order to use the program. Once you have entered the necessary parameters via the online form, your query will be processed by EJOT fastening specialists using Delta Calc. The results will be sent to you by email.



More information

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