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CSK pozi screws - Cone shaped, with flat outer face and tapering inner face allowing it to sink into the material. The angle of the screw is measured as the full angle of the cone.
PHILIPS SCREWDRIVERS WILL WORK WITH THESE SCREWS IN THE SAME WAY IT WOULD WITH A PHILIPS HEAD SCREW
The Pozidriv, sometimes misspelled Pozidrive, screw drive is an improved version of the Phillips screw drive. Its advantage over Phillips drives is its decreased likelihood to cam out, which allows greater torque to be applied. In ANSI standards it is referred to as type IA. It is very similar to, and essentially compatible with, the Supadriv screw drive.
Phillips drivers have an intentional angle on the flanks and rounded corners so they will cam out of the slot before a power tool will twist off the screw head. The Pozidriv screws and drivers have straight sided flanks.
The Pozidriv screwdriver and screws are also visually distinguishable from Phillips by the second set of cross-like features set 45 degrees from the cross. The manufacturing process for Pozidriv screwdrivers is slightly more complex. The Phillips driver has four simple slots cut out of it, whereas in the Pozidriv each slot is the result of two machining processes at right angles. The result of this is that the arms of the cross are parallel-sided with the Pozidriv, and tapered with the Phillips.
This design is intended to decrease the likelihood that the Pozidriv screwdriver will slip out, provide a greater driving surface, and decrease wear. The chief disadvantage of Pozidriv screws is that they are visually quite similar to Phillips, thus many people are unaware of the difference or do not own the correct drivers for them, and use incorrect screwdrivers. This results in difficulty with removing the screw and damage to the slot, rendering any subsequent use of a correct screwdriver unsatisfactory. Phillips screwdrivers will fit in and turn Pozidriv screws, but will cam out if enough torque is applied, potentially damaging the screw head. The marker lines on a Pozidriv screwdriver will not fit a Phillips screw correctly, and are likely to slip or tear out the screw head. |