Many projects are made much easier by the inclusion of shoulder screws in the design. Shoulder screws are actually machine bolts that incorporate a barrel-like feature between the threaded section and the screw head. Acting like an axle, the shoulder screws provide a natural place to mount a wheel, hub or gear without requiring a complete axle to be engineered into the project. The design of the shoulder screw makes it a good choice for guiding belts and cables, as well as creating places to hook straps and cords.
Any project that will require rolling wheels is a good candidate for the use of shoulder screws. The shoulder screws can be positioned around the lower section of the project and the wheels can be attached to the project using the screws. The screws are available in a wide variety of sizes, making it possible to match nearly any size of wheel hub with a correctly-sized shoulder screw. When running the screws into a strong and thick material, the design is able to support a great deal of weight.
Some projects, such as conveyor belts or roller belt systems, can be made utilizing shoulder screws to support the belt assembly or to create several different lengths of rollers. The screws can be distributed within the design to create a virtual surface of rollers that parcels and merchandise can be rolled upon, much like a commercially-available rolling conveyor line. The shoulder screw assembly can be made even more durable when using a bearing-equipped wheel or roller on the screw shafts. In doing this, the wheels are able to roll much easier and the amount of friction that could potentially wear against the screw shank is reduced to nearly nothing.
There are also projects, such as mechanized sprayers, lawn sprinklers and fertilizer spreaders, that can use shoulder screws to support the gears required for the operation of the device. Using the screws can virtually eliminate the requirements of full-length steel axles to support gears, sprockets and drive components within the body of the devices. The complete assembly can be produced using shoulder screws on one side of the mechanism and then be finished by bolting the outer cover onto the completed assembly. A small dab of grease onto the barrel of the screw will provide long-lasting lubrication for most projects. The screws have the potential to make the attachment of rollers for use on door tracks and drawer slides a very simple and easy step in that type of project.