The normal slotted head is best used which has a flat screwdriver, whilst the cross-shaped indention is most effective suited to a Phillips screwdriver. A Robertson screw has a sq.-shaped indention and needs a matching driver head. Thread forming screws are much like thread chopping screws, but as opposed to https://timco-screws11974.blogolize.com/the-ultimate-guide-to-wood-screws-67929777