The REMFORM® ‘F’ screw is a derivative of the REMFORM® screw for plastics and was primarily designed for magnesium applications.
The steep trailing flank on the REMFORM® ‘F’ screw’s unique asymmetrical thread form is engineered to resist pullout, whether it be applied by a tensile load or induced by torque. When a threaded fastener is tightened, the trailing flank has to resist being pulled toward the direction of the head. Nearly all the load is between the screw’s trailing flank and the adjacent nut thread’s flank. The leading flank is most influential in forming the mating thread. The narrow angle intercepting a radius form on the lead flank promotes efficient material displacement and flow.
The narrow tip of the REMFORM® ‘F’ screw minimizes disturbance of the magnesium during thread forming. REMFORM® ‘F’ screws have a finer pitch than REMFORM® screws. The fine pitch provides the involvement of several threads in a minimal length of engagement. REMFORM® ‘F’ screws require modest lengths of engagement to reach full strength of the fastener, minimizing the need for excessively deep pilot holes.
Figure 2 shows that REMFORM® ‘F’ screws form clean uniform internal threads in magnesium, even when multiple cycles are used.
Figure 3 shows “black paper” which was held below the magnesium nut member while a REMFORM® ‘F’ screw formed threads and was driven in and out for five cycles. The lack of magnesium chips and debris on the black paper also shows that REMFORM® ‘F’ screws create a strong uniform mating thread that maintains integrity through multiple in and out cycles.