I seemed to have ruined all my 'phillips' type screw drivers...those ones with the + instead of - at the working end.How do you know which size to use? They all seem to work initially, but then they twist with out actually moving the screw which over time ruins the screwdriver. TIA
The right one to use is the biggest one that fits fully in the slot.But, there are two sorts, Phillips and Pozidrive, which have very slightly different profiles. Phillips are designed to torque out when too much force is applied, Pozidrive are designed not to.Pozidrive screws are marked by having small cuts at 45 degrees to the main cross slot. Modern screwdrivers often have a symbol on them with or without the cross lines to indicate Pozidrive (with) or Phillips (without).Using the wrong screwdriver in the wrong screw type will wear both the screw heads and the screwdriver tips. http://en.wikipedia.org/wiki/Pozidriv
The screwdriver should be a really snug fit in the slot. If not, it's the wrong size.Cheap ones don't last very long. Make sure that the screwdriver is directly in line with the screw.HTHBob
But, there are two sorts, Phillips and PozidriveI have used Supadrive which seems similar to Pozidrive. Is there a difference?
I have used Supadrive which seems similar to Pozidrive. Is there a difference?I believe the difference is in the screw. Supadrive allow a small angular offset between the screw and the screwdriver. Pozidrive have to be directly in line.Most screws found in the UK are Pozidrive or Supadrive rather than Phillips. However, Pozidrive screwdrivers will not fit Phillips screws. A good set of each should last most people many years if the correct one is always used.There are others such as JIS (Japanese Industrial Standard). JIS is very similar to Posidrive.If a screwdriver is allowed to slip, it wears out very rapidly. Screws which come with some items are of poor quality and are best replaced. A few good quality screws are cheaper than a screwdriver.Julian F. G. W.