Custom PT Thread Pan Head Tapping Screw Manufacturers & Suppliers

Type B and AB tapping screws use wide 60° thread flank angles designed primarily for sheet metal or heavy structural wood. When driven into thermoplastics, these wide flanks generate excessive outward radial pressures that cause molded boss walls to expand and crack. In contrast, PT threads use an acute 30° flank angle with an enlarged thread root depth. This profile facilitates smooth thermoplastic displacement, lowers driving resistance, and increases dynamic pull-out resistance without bursting small plastic bosses.

As a standard rule of thumb for engineering thermoplastics (such as ABS or PC), the pilot hole diameter should match the screw's thread pitch diameter (approximately 0.80 to 0.85 times the nominal outer thread diameter). For stiffer glass-filled resins (like PA66-GF30), the pilot hole is generally adjusted upward to roughly 0.88 times nominal diameter to reduce insertion torque. The outer boss diameter should typically be 2.0 to 2.5 times the screw's nominal diameter. Our engineering department can calculate exact boss geometries and counterbore depths based on your CAD models and material specifications.

Yes. Unlike standard thread-cutting fasteners that chip away plastic shavings upon re-entry, PT screws cleanly form reusable female threads via controlled plastic deformation. During reassembly, turning the screw backward slightly until it drops into the existing thread track allows it to be retightened up to 5 to 10 service cycles while maintaining 80% or more of its original clamping force.

While Phillips (cross recess) drives remain a practical, economical choice for general manual assembly, Torx (6-lobe / ISO 10664) drives are strongly recommended for automated or robotic assembly cells. Torx recesses provide near-vertical flank contact angles, virtually eliminating cam-out issues, reducing operator fatigue, extending drive bit lifespan, and facilitating accurate torque monitoring on automated assembly screwdrivers.

Standard stocked catalog components ship within 48 to 72 hours. For custom non-standard orders built to customer prints (involving specialized shank steps, proprietary drive bits, or non-standard alloys), initial tooling and PPAP first-article samples are delivered in 7 to 10 business days. Following sample validation, volume production runs typically require 15 to 20 days. Minimum order quantities start at 50,000 units for standard wire diameters and 100,000 units for specialized custom alloys.