Drilling and tapping screws allow users to fasten materials together without preparing them in advance. They can create pilot holes, cut threads into the fastening surface, or a combination of both. Self-drilling screws feature cutting grooves on their tips that cut their pilot hole as they are driven. Sheet metal screws have a flanged head, a pointed tip, and a fine thread pitch. This helps reduce damage to thin or weak metals like aluminum or tin. Drywall screws have coarse threads, a pointed tip, and a flared head designed to hold drywall sheets onto a wall frame. Wood screws have a pointed tip and coarse threads that dig into wood parts and hold them together. Hex head lag screws are wood screws that are meant for higher loads. They are larger than wood screws and are fastened using a wrench or socket, rather than a screwdriver. Thread-cutting and thread-forming screws feature cutting grooves on their tips that cut threads into a pilot hole as they are driven.