Fasteners are intricate and complicated, until you sort through and understand the many differences that is. From the length to the material used, the driver type and the threading – screws especially seem to come in a vast selection of confusing choices. How do you know which head screws you are supposed to order for your project? You might think that there are only two – flat heads and pan heads – but the choice is quite a bit wider than that and in order to choose well, you need to know where the differences lie. This is where Contractors can sometimes come in handy as they tend to know their nuts and bolts as well as other Fasteners such as Hex Bolts and Hex Head Cap Screws.

Flat Head and Trim Heads

These are what most people think of when they are asked to pick up deck screws. A flat head is common to both and they can both be countersunk into the wood or composite material. Alternatively, both flat head and trim head screws can be inserted into a predrilled hole and covered with a plug to ensure an ultra smooth finish. Generally a trim head screw is chosen when a surface mount is required, though.

Pan Head and Washer Heads

These are the opposite of flat head screws, in that they are designed to sit on top of the surface. For that reason they are most often seen on heavy plastics and metal applications where countersinking is not an option. But the main benefit of both the pan head and the washer head screws is that the shape of the head allows for better distribution of the load. You can use a washer head screw just like you would a screw and washer combo, except you don’t have the hassle of handling two fasteners.

Other Types of Screws

You may also come across oval head screws. Similar to a round head screw that has been flattened, this type of screw is used to provide a snag free surface that is relatively smooth. Nautical applications put the oval head screw to good use.

Truss head screws offer a very large head that provides more surface area to distribute the load. Often used with a nut on oversized holes, this type of screw is sometimes called a bolt as well.