Hi
- Lo Plastic Tapping Screws
The Hi-lo
fastener, with its unique thread form, improves fastener
performance in a broad range of automotive grade plastics.
This fastener is designed with a double lead, consisting
of a high and a low thread. The high thread is sharper than
a conventional thread, having a 30° included angle as compared
to the conventional 60° included angle. The low thread has
the 60° included angle and a height that is 40% to 50% of
the high thread height.
The superior
performance of the Hi-Lo fastener increases product quality
and decreases costs. The 30° included angle of the high
thread form reduces radial or bursting pressure over that
generated by a conventional 60° included angle thread form.
Boss cracking in plastic is dramatically reduced and smaller
diameter bosses can often be specified.
The Hi-lo
screw thread configuration has a smaller minor diameter
than a conventional screw. The high threads make a deeper
cut into the material leaving a greater volume of material
between the threads. There is also a greater amount of material
in contact with the high, sharp thread and the axial shear
area is increased. All of this contributes to greater resistance
to pull-out and stronger fastening. |
