Chipboard screws were created to fasten low, medium and high density chip board. Because chipboard has no natural grain to resist the screw from withdrawing, these screws often have grippers around their head called nibs. The screws are skinny to avoid splitting with a coarse grain to lock the board in place. Many of these screws are self tapping, so there is no need to bore holes first. Some have special ridges around their heads that remove the chipboard material when countersinking.