HI - LO Fastener for:
Plastics, Particle Board, Masonite and Wood

SUPERIOR PERFORMANCE CHARACTERISTICS OF THE HI-LO FASTENER

1. REDUCED CRACKING, SPLITTING AND BOSS BREAKAGE
The superior performance of the Hi-Lo screw increases product quality and decreases costs. The 30° included angle of the high thread form reduces radial or bursting pressures to one-half that generated by the conventional 600 included angle thread form. Boss cracking in plastic is dramatically reduced and smaller diameter bosses can often be specified. In wood applications, even when driving close to the edge, splitting is greatly reduced due to this lower bursting pressure.

2. INCREASED PULL-OUT STRENGTH
The Hi-Lo thread configuratiohhas 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, flat thread and the axial shear area is increased. All of this contributes to greater resistance to pull- out and a considerably stronger fastening.

The results of aseries of tests show conclusively that the Hi-Lo ~ thread form is capable of generating considerably greater resistance to pull-outforces than a regular Type Bthread form. 8-18 screws with .0002" cadmium plate were used in the tests. The screws were driven to a depth of .375" in bosses with diameters of .400". The recommended hole size for the Type B was .144". The Hi-Lo screw required a .128" hole.

3. LOWER DRIVING, HIGHER STRIPPING TORQUES
The 30° included angle of the high thread displaces less material when it is driven into plastic or wood and, therefore, requires lower driving torques. A greater amount of material remains between the high threads, increasing the stripping torque. Low driving torque and high stripping torque provide
maximum protection against stripping problems. Comparative tests were conducted to measure the drive and strip differential between Hi-Lo screws and Type B screws in various materials. Again, 8-18 screws with .0002" cadmium plate were used in the specific tests with the following results: