high-strength bolt,Types of screws and bolts
Description：high-strength bolt--Threaded fasteners either have a tapered shaft or a non-tapered shaft. Fasteners with tapered shafts are designed to either be driven into a substrate directly or into a pilot hole in a substrate.
Types of screws and bolts
Threaded fasteners either have a tapered shaft or a non-tapered shaft. Fasteners with tapered shafts are designed to either be driven into a substrate directly or into a pilot hole in a substrate. Mating threads are formed in the substrate as these fasteners are driven in. Fasteners with a non-tapered shaft are designed to mate with a nut or to be driven into a tapped hole.
Fasteners with a tapered shaft (self-threading screws)
There is not a universally accepted definition of the word, screw. It generally refers to a smaller threaded fastener with a tapered shaft. See the section Differentiation between bolt and screw above for a more detailed discussion.
Generally has an unthreaded portion of the shaft below the head. It is designed to attach two pieces of wood together.
Lag screw (lag bolt)
Similar to a wood screw except that it is generally much larger running to lengths up to 15 inches (381 mm) with diameters from ¼" to ½" (6.4–12.25 mm) in commonly available (hardware store) sizes (not counting larger mining and civil engineering lags and lag bolts) and it generally has a hexagonal head drive head. Lag bolts are designed for securely fastening heavy timbers (post and beams, timber railway trestles and bridges) to one another, or to fasten wood to masonry or concrete.
Lag bolts are usually used with an expanding insert called a lag in masonry or concrete walls, the lag manufactured with a hard metal jacket that bites into the sides of the drilled hole, and the inner metal in the lag being a softer alloy of lead, or zinc amalgamated with soft iron. The coarse thread of a lag bolt and lag mesh and deform slightly making a secure near water tight anti-corroding mechanically strong fastening.
Sheet metal screw (self-tapping screw, thread cutting screws)
Has sharp threads that cut into a material such as sheet metal, plastic or wood. They are sometimes notched at the tip to aid in chip removal during thread cutting. The shaft is usually threaded up to the head. Sheet metal screws make excellent fasteners for attaching metal hardware to wood because the fully threaded shaft provides good retention in wood.
Self-drilling screw (Teks screw)
Similar to a sheet metal screw, but it has a drill-shaped point to cut through the substrate to eliminate the need for drilling a pilot hole. Designed for use in soft steel or other metals.
Specialized screw with a bugle head that is designed to attach drywall to wood or metal studs, however it is a versatile construction fastener with many uses. The diameter of drywall screw threads is larger than the shaft diameter.
Particle board screw (chipboard screw)
Similar to a drywall screw except that it has a thinner shaft and provides better holding power in particle board.
Similar to drywall screw except that it is has improved corrosion resistance and is generally supplied in a larger gauge.
Double ended screw (dowel screw)
Similar to a wood screw but with two pointed ends and no head, used for making hidden joints between two pieces of wood.
Screw eye (eye screw)
Screw with a looped head. Larger ones are sometimes call lag eye screws. Designed to be used as attachment point, particularly for something that is hung from it.