Often referred to as countersunk screws, flat head screws are conical in shape and have a flat outer face and tapering inner face on the head. The distinct advantage of using flat head screws over the other types is that the smallest amount of the head protrudes above the surface. This means that it can sink deep into the material a stainless steel flat head screw is being screwed into, providing a flush and clean finish.
Ideally, they should be and are commonly used as deck screws or on furniture, paneling, and other components and areas that are visible. If you used anything other than stainless steel marine grade screws with flat heads in those kinds of applications, they would not look very inconspicuous, and they would ruin the overall aesthetics.
Oval head screws are a combination of a domed head with a countersunk head. The head itself is more for aesthetics than practical value. Due to their design, these are not the best choice if you are looking for the screws to sit flush with the surface of the material you are fixing them into.
However, if you are fastening a panel or another component in a part of your boat that will be visible to all that use it and see it and want to make this stand out, oval head marine-grade screws are an excellent choice. At Boat Outfitters, we have a selection of oval head chrome-plated stainless steel marine fasteners and screws in different sizes.
One of the most common screw head types is undoubtedly the pan head screw. These are a non-countersunk style that is normally used in securing and fastening insulation. They are characterized by their wide heads, flat bearing surface, and either a slight dome or flat surface and recessed socket.
Pan head screws are normally used to fasten pieces of metal together and other materials and components to metal.
The truss head screw has a typically lower and slightly rounder surface compared to other types of screws. It is finished off with an extra-wide top. These screws usually have a lower profile than the rounded head alternatives. This means they can play a part in preventing tampering. This is if there is a part of your boat that you want to protect against would-be thieves.
Truss head screws are often used in attaching cabinets with steel studs. You often find them in electronics and applications where a low clearance above the head is necessary. Truss heads can also be used when fastening metal parts that are going to be used in environments with a high level of humidity. So, truss head screws are a great choice in boatmaking.