A wood screw generally has a partially unthreaded shank below the head. These can withstand only torsion of one side of shaft rotation. Spring pins are an alternative Dutch key component, instead of solid dowel pins.
Unsourced material may be challenged and removed. Plow bolts provide a smooth surface metric woodruff key slot dimensions attaching a plow moldboard to its beam, where a raised head would suffer from soil abrasion.
Inch-sized wood screws in the U. Stainless steel shoulder screws are used with linear motion devices such as bearings, as guides and as pivots in electronic and other critical mechanical applications. The screw is fastened by hitting the head with a hammer and is not intended for removal.
By simply driving setscrews into selected holes, the hub mechanism conveniently operates to rigidly lock or definitely release from the shaft, without hammering or hub-pulling. A Hirth joint is similar to a spline joint but with the teeth on the butt of the shaft instead of on the surface. Fasteners with a non-tapered shank[ edit ] American name Description anchor bolt A special type of bolt that is set in wet concrete, with the screw threads protruding above the concrete surface.
Because of this, the amount of torque required to achieve a given preload is reduced. The most often used type is the socket set screw, which is tightened or loosened with a hex key.
The more obscure ones may not be listed here. Like aerospace and nuclear power, this field involves some of the highest technology for fasteners, as well as some of the highest prices, for the simple reason that performance, longevity, and quality have to be excellent in such applications.
Shoulder screw specifications call out the shoulder diameter, shoulder length, and threaded diameter; the threaded length is fixed, based on the threaded diameter, and usually quite short.
An additional advantage is a stuck key can be removed from a shaft with a hammer blow, the circular profile will push the key out of the slot, as opposed to a standard key which will need to be pushed axially, or pulled out of its slot. This limited shear strength specification is designed to sustain normal operation, but then give way in the event of excessive shaft torque, thus protecting the rest of the machine from damage.
List of abbreviations for types of screws[ edit ] This section does not cite any sources.
The extra spacing between linked terms below helps the reader to see the correct parsing at a glance. InAnthony defined it as screw with a hex head that was thicker than a bolt head, but the distance across the flats was less than a bolt's.
When the appropriate torque is reached the spline shears off. Installation and removal of any size tensioner is achieved with hand tools, which can be advantageous when dealing with large diameter bolting applications. The coarse thread of a lag bolt and lag mesh and deform slightly making a secure near water tight anti-corroding mechanically strong fastening.
These are rarely used keys, to transmit lower power to the driven members e.
The shank is usually threaded up to the head. A hex key sometimes referred to as an Allen wrench or Allen key or hex driver is required to tighten or loosen a socket screw. In some screws, the head can be removed by breaking it after installing the screw.