Step 22: Mortorq®
The Mortorq Spiral Drive recess developed by Phillips, is much shallower than other standard recesses on the market, and can be put into a much shallower head without affecting the strength of the screw. This assembly allows for a shallower counterbore, reducing material thickness without compromising the joint strength, because it does not affect the material thickness below the counterbore. A Mortorq recess uses full wing contact with driver bit in both drive and removal directions.
Advantages and Disadvantages of Mortorq
Aerospace designers have had to compromise on fastener performance. Previously, shallow head styles had poor torque transfer and damaged easily while robust drives required thicker material and added weight. The unique shape provides full contact of the driver over the entire recess wing resulting in extremely high torque capability without the risk of damage. Depth of the recess in the fastener head is minimized resulting in true high performance in 100 degree flush head and shear head applications. The open recess concept allows driver to recess misalignment and compensates for paint build-up without degrading torque performance. Workers can easily install and remove panel and structure fasteners at odd angles without high muscle stress or fear of damage to surrounding surfaces. Larger driver cross-sections and curved surfaces provide extended tool life and resistance to tensile fatigue fracture when used with high load pulse tools.