CHIPBOARD SCREW :

• A chipboard screw or particleboard screw is a self tapping screw with a thin shaft and coarse threads. Chipboard is a made up of resin and wood dust or wood chips, so chipboard screws are made to grip this composite material and to resist withdrawing. The screws solidly fasten chipboard to chipboard or chipboard to other materials such as natural wood. Many different screw types, material and sizes exist.
• Chipboard screws were created to fasten low, medium and high density chipboard. 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 even have special ridges around their heads that remove the chipboard material when countersinking.