304 Stainless Steel Button Head STAR DRIVE Torx Socket Cap Machine Screw

A machine screw is a type of fastener that, like, other fasteners, is used to join two or more objects. Machine screws are unique, though, because of their size. The American Society of Mechanical Engineers (ASME) defines machine screws as featuring a diameter of up to 0.75 inches. They can be smaller than 0.75 inches in diameter, but they can’t be larger than this size. As a result, machine screws are generally smaller than most other types of screws.

In addition to a diameter of 0.75 inches or less, machine screws are characterized by uniform threading. What does this mean exactly? Well, screws typically feature either uniform or tapered threading. Uniform threading means the exterior threading — the helical ridges on the outside of the screw — remain the same size from the top of the screw to the bottom. In comparison, tapered threading means the screw’s threading expand taper or expand towards the bottom. Machine screws feature uniform threading that remains the same size from the top to the bottom.