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Spotlight on Thread Forming Screws for Plastic
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Thread forming screws were specifically designed for use in plastics to provide driving ease and improved holding power. Apex Fasteners offers a broad range of thread forming screws for plastic to provide the right part for every application from soft plastics to hard and from low to high vibration environments. |
 | PT® ScrewThe PT® screw features a 30° thread angle which reduces radial stresses, provides increased thread depth, lowers installation torque, and improves material flow due to a high axial component. The pitch developed resists vibrational loosening, provides optimum non-reversibility, and balances the load between the fastener and plastic. The profiled thread root provides maximum resistance to relaxation and improved retention of clamp load.
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 | Delta PT® ScrewThe Delta PT® represents the next advancement in design of the PT® screw and features a compound geometry of the flank angle of the thread. Improvements include better deformation of the plastic material during the fastening process, increased service life of the joint both in case of static and dynamic stress. Up to 50% improved torsional and tensile strength for the same diameter fastener. The optimized pitch provides a higher clamp load at low contact pressure by increased flank engagement.
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 | Plastite®PLASTITE® TRILOBULAR™ thread rolling screws were developed specifically for use in plastics. They combine a unique TRILOBULAR™ cross-sectional form with deep, wide, spaced threads.Easier to drive. Three swaging lobes with full relief of the thread form reduce driving effort and operator fatigue. More holding power. The three-lobed design of PLASTITE® screws takes full advantage of the cold flow characteristics of many plastics by allowing plastic material to recover and fill in between the lobes. This establishes maximum resistance to vibrational loosening. In addition, the screws' deep, coarsely-spaced threads provide a heavier shear area and deeper thread engagement in the plastic, further enhancing holding capabilities. |
 | REMFORM® ScrewsDesigned primarily for plastic applications, the REMFORM® Screw is a thread rolling fastener with a unique thread form to provide superior performance in today's wide range of plastics. The asymmetrical thread profile minimizes radial hoop stress to reduce boss bursting. The narrow tip angle also reduces stress in the plastic nut member. |
 | REMFORM® II™The REMFORM® II™ screw is a thread-forming fastener with a unique thread form to provide superior performance in a wide range of engineered plastics. The asymmetrical thread minimizes radial hoop stress to reduce boss bursting. The narrow tip angle also reduces stress in the plastic nut member.Reduced Hoop Stress The radial tip thread crest of REMFORM® II™ screws reduces sharp corners, which reduces radial hoop stress in the plastic caused by thread-forming. When a threaded fastener is tightened, nearly all of the axial tightening load is opposed by the trailing or pressure flank of the screw and the mating thread flank of the internal thread. The steep pressure flank transfers most of the resultant tightening load in the axial direction, minimizing boss bursting tendencies created by the radial force. The axial force is over 4.5 times greater than the radial force. The Unique Radius Flank™ Thread Form REMFORM® II™ screws employ the Unique Radius Flank™ asymmetrical thread. The leading thread flank is most influential in forming the mating thread. The intercepting radius form on the leading flank is there to promote efficient material displacement and material flow. The pressure flank which opposes the fastener head is engineered to resist pull-out forces, whether they be applied by a tensile load or induced by torque. The steep pressure flank has a subtle radius designed to increase resistance to pullout and to efficiently develop tension. It also provides excellent material contact resulting in a high resistance to the internal threads stripping. In applications where the failure mode is fastener fracture, the high torsional strength of REMFORM® II™ fasteners ensures a high failure torque and improved resistance to loosening. This unique thread form and its narrow tip angle efficiently displace material and therefore require minimal energy to form an internal thread. The tip also utilizes a radius to better create the internal thread without increasing hoop stress in the plastic. |
 | REMFORM® II HS™REMFORM® II HS™ fasteners were developed to combine the features of REMFORM® II™ and REMFORM® II F™ fasteners with an optimized gap between the threads and core diameter. These optimizations allow a better flow of the mating plastic material and accept a higher amount of material between the flanks. This reduces overstressing of the plastic material during the assembly process.The optimized core diameter provides a higher torsional strength, advantageous when the fastener is used in higher strength or fiber-reinforced materials. In applications with higher axial thread engagement, the optimized pitch allows more threads to be in contact with the plastic material. The REMFORM® II HS™ fastener also uses the Unique Radius Flank™ asymmetrical thread design which is the standard for all REMFORM® fasteners. |
 | Hi-Low ScrewsHi-low screws have a reduced minor diameter and therefore displace less plastic material and minimize stress. These screws have a double lead high and low thread with the high thread having a 30 degree thread form that further minimizes material displacement while providing positive thread engagement. Hi-low screws are tapping screws and therefore normally require a preformed hole to be properly employed. Hi-low screws often have a reduced head size as a standard feature. |
