STAINLESS STEEL SCREWS FOR PLASTICS

Screws for Plastics

Screws for Plastics are thread-forming screws designed to cut their own mating thread directly into a moulded or drilled hole in a plastic component, rather than engaging with a pre-tapped fixture or a separate nut. As the screw is driven in, its thread profile displaces and re-forms the surrounding plastic to create a load-bearing thread path in a single operation. PTS's Screws for Plastics range covers two dedicated thread-form families, Polytech 30 and Polyfix 45, offered across a selection of head and drive styles to suit different assembly and finish requirements.

Materials
As with the rest of the PTS range, Screws for Plastics are supplied in stainless steel; check the individual product listing for the exact grade of a specific line.

Polytech 30
The Polytech 30 range is the larger of the two families, available in Pozi Pan, Phillips Pan, Pozi Countersunk, Phillips Countersunk, Hexalobular Pan, Hexalobular Countersunk, Pozi Flanged and Hexalobular Flanged variants. This spread of head and drive combinations makes Polytech 30 the more flexible choice where a specific head profile or drive type is needed to match existing assembly tooling or a particular finished appearance.

Polyfix 45
The Polyfix 45 range covers Pozi Pan, Pozi Countersunk, Hexalobular Pan, Hexalobular Countersunk and Pozi Flanged variants. Polytech 30 and Polyfix 45 use different thread geometries, each suited to a different combination of plastic hardness and boss design — Polytech 30 is the more widely specified of the two, while Polyfix 45 suits specific boss and hole-tolerance combinations. The two ranges are not simply interchangeable sizes of the same thread, so the correct range for an application should be confirmed against the boss and hole design it is being fitted to.

FAQs
What's the difference between Polytech 30 and Polyfix 45?
Both are thread-forming screw ranges purpose-built for plastic, and both are differentiated from one another by thread profile rather than by head style. Thread-forming screws for plastics are generally differentiated by thread angle and pitch to suit different combinations of plastic hardness and boss design — Polytech 30 is the more widely specified of the two, offered across the broadest range of head and drive options, while Polyfix 45 suits specific boss and hole-tolerance combinations. For a specific application, match the range to the boss design using the supplier datasheet or contact PTS.

Why not just use a standard self-tapping screw in plastic?
A standard self-tapping screw is generally designed to cut into metal or wood, using a sharper thread that shears and removes material as it's driven in. In a plastic boss this cutting action can generate stress concentrations and even crack or split the plastic around the hole, and the resulting thread often has poor pull-out resistance if the screw is removed and reinserted. A dedicated thread-forming screw for plastics uses a shallower, rounder thread profile that flows and displaces the plastic rather than cutting it, reducing stress on the boss and giving a stronger, more reusable thread engagement.