Materials are usually either stainless steel, BZP, or brass. Socket screws are those with a hex (Allen) drive and include grub screws, countersunk, cap, or button head. Machine screws are available in slot or cross drive with round or countersunk heads in a wide range of lengths and thread sizes. Hex head screws also come in a wide range of sizes with a standard bolt head. Dowel screws, have a coach thread at one end and a machine thread at the other, for connecting timber to other materials. For our extended screws range view our Fixings and Anchors category.