a cap screw has a top bigger than the threaded portion [a cap ]. the cap screw does not sit flush with the material being screwed into. a machine screw has a tapered top that fits into a countersunk hole and when screwed in is flush with the surface being screwed into; 20 people found this useful. Hex cap screws feature a washer face under the head and a chamfered point. Cap screws are made up of low-carbon steel. heremonly used in construction or repair projects. A machine screw is generally a smaller Fastener threaded the entire length of its shank that usually has a … Head Shape. A shank between the head and the threads of a cap screw and a thin spacer under the head helps the cap screw rotate. The height of the head of a cap screw is slightly smaller than a bolt. Cap screws have round heads, unlike bolts that have square heads that can be wrenched easily.

Technically, a bolt is installed by turning a nut to tighten the fastener, while a cap screw in installed by turning the head of the bolt to assemble and tighten. Therefore, cap screws are often threaded into a tapped hole on a piece of equipment or machinery or installed in some other OEM application. A tap bolt should be assembled with a nut and the nut should be turned to tighten the assembly. A fully threaded hex cap screw can be used with or without a nut (tapped hole) and can be assembled by turning the head or the nut during assembly. Typically, in our industry, if someone orders a hex bolt you can always supply a hex cap screw . Sep 16, 2007 just now. Actually, the difference between a bolt and screw is based on its application, not appearance. A bolt is used with a nut to produce a clamping force to hold materials together; whereas a screw interlocks threads with the material itself (no nut on the end).

Feb 21, 2019 @wanderer, the difference between bolts and screws are that both are externally threaded fasteners, but a bolt is intended to be tightened or released by a nut, while a screw is intended to be inserted into holes in assembled parts being tightened by torquing the head. What Is the Difference Between a Screw and Bolt? A screw is a fastener that has a ridge or thread encircling the entire length of the device, while a bolt has a smooth shaft and a threaded end. Screws have heads with a depression indicating the type of driver necessary for fastening. A set screw is generally a headless screw but can be any screw used to fix a rotating part to a shaft. The set screw is driven through a threaded hole in the rotating part until it is tight against the shaft. The most often used type is the socket set screw , which is tightened or loosened with a hex key or hex driver.

Hex cap screws may have a shoulder in longer sizes, which makes them stronger. Both are typically installed with a nut and designed to be driven by a wrench or socket driver. And last but not least, if a hex cap screw is small enough to lose its shoulder it can also be considered a tap bolt.