This screw is stable and very uniform with both a Phillips and flathead driver fitting in it to tighten and loosen. The screw is for moderate applications as drivers often slip out once they reach ...

Second, the driver won’t slip out even at high levels of torque. The Canadian Model T Ford used over 700 Roberson screws. A Phillips driver, although those screws look suspiciously like Robertsons.

The additional contact points spread the driving torque and prevent the kind of “cam-out” you get with Phillips or ...