EJOT DELTA PT® S

 

The DELTA PT® screw is a proven fastener element for thermoplastics, which can also be used in many thermosetting plastics.

The expansion, which happens during thread forming, overextends the capability of some thermosets.

Therefore, the DELTA PT® S has been developed. Introducing a cutting edge reduces radial stress during thread cutting in the thermoset material.

Benefits of the DELTA PT® screw S

• Minimized radial stress due to low thread flank angle and cutting-edge
• With optimized thread pitch, the screw offers high retention when used in thermosets
• High tensile strength
• High torsion strength
• Material through hardened steel grade PT10
• Cost-effective when using standard norm parts
• Process-safe assembly
• Repeat assembly is possible
• Possible elimination of threaded inserts

The Cutting Edge

The DELTA PT® screw S is made with a DELTA PT® thread form and has an additional feature of a milled cutting edge over approximately three pitches at the lead thread end of the screw.

Design Guidelines

The DELTA PT® screw without cutting edge is suitable for assembly in many thermosets. The toughness and impact strength of the thermoset material should be established to establish if the cutting notch is required. The initial evaluation can establish if the cutting edge is necessary. Assembly tests on original components will give final performance confirmation. The geometry of the boss design should generally be shown on the right. It is essential that the filling of it is homogeny, especially in conjunction with long fiber materials.  Extra fins on the boss can be of benefit. 

d₁= Nominal-Ø of the screw

d_c = d₁ + 0,2 mm

Dimensions

The possible dimension of the DELTA PT® screw with cutting-edge is limited due to manufacturing technique.

The current lengths and diameters available are listed in the matrix to the right. Parts are produced with the standard DELTA PT® styles.

 

Special geometries upon request.
Full thread only to 50mm length possible.