Threaded Fasteners BOLTS A bolt is a form

Threaded Fasteners

BOLTS A bolt is a form of threaded fastener with an external male thread. closely related to, and often confused with, screws. The defining distinction is in their intended purpose: – bolts are for the assembly of two unthreaded components, with the aid of a nut. – screws in contrast are used with components that have at least one containing its own thread. Where a fastener is used with a nut, it is a bolt rather than a screw.

NUTS fastener with a threaded hole. used opposite a mating bolt to fasten parts together. common shape is hexagonal, for similar reasons as the bolt head - 6 sides give a good angles for a tool to approach from (good in tight spots) other specialized shapes exist for certain needs, such as wing nuts for finger adjustment and captive nuts for inaccessible areas. A wide variety of nuts exists, from household hardware versions to specialized industry-specific designs that are engineered to meet various technical standards.

WASHERS a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a screw or nut. other uses are as a spacer, spring, wear pad, locking device, and to reduce vibration (rubber washer). are also important for preventing corrosion, particularly by insulating steel screws from aluminium surfaces. Washers can be categorized into two main types; – 'plain washers', which spread a load, and prevent damage to the surface being fixed, or provide some sort of insulation such as electrical; – 'locking washers' which prevent fastening loosening by preventing unscrewing rotation of the fastening device; locking washers are usually also spring washers.

BOLTS AND SCREWS There is no universally accepted distinction between a screw and a bolt. The following may help in identifying the difference: – A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut. – A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head. Screws are used with components that have at least one containing its own thread. Where a fastener forms its own thread in the component being fastened, it is a screw. This is most obviously so when the thread is tapered (i. e. traditional woodscrews).

Screw and Bolt Head Types

NON-THREADED FASTENERS Unit 3 - Product Design

COMMON NON-THREADED FASTERNERS Nails Pins Keys Rivets

NAILS a small metal spike with a broadened flat head, driven typically into wood with a hammer used as a fastener, as a peg to hang something have a sharp point on one end a flattened head on the other, but headless nails are available. Nails are t driven into the workpiece by a hammer or nail gun. manufactured in a variety of shapes, sizes, and metals to complete almost any fastening job. made of steel, but other types -- aluminum, brass, nickel, bronze, copper, and stainless steel -- are available for use where corrosion could occur. In addition, nails are manufactured with coatings -- galvanized, blued, or cemented -- to prevent rusting and to increase their holding power. Nails shorter than 1 inch are called brads; nails longer than 6 inches are called spikes.

COMMON TYPES OF NAILS Common Nails: for most medium to heavy construction work, this type of nail has a thick head and can be driven into tough materials. Box Nails: Lighter and smaller in diameter than common nails, box nails are designed for light construction and household use. Finishing Nails: Finishing nails are lighter than common nails and have a small head…. often used for installing paneling and trim where you do not want the nail head to show. Roofing Nails: Usually galvanized, roofing nails have a much larger head than common nails. This helps to prevent damage to asphalt shingles. Drywall Nails: made for drywall installation are often ringed and have an indented head. Annular-ring nails have sharp ridges all along the nail shaft, providing greater holding power. Masonry Nails: designed for use with concrete and concrete block. Masonry nails should not be used where high strength is required. Fastening to brick, stone, or reinforced concrete should be made with screws or lag bolts.

PINS A pin is a device used for fastening objects or material together. Pins often have two components: a long body and sharp tip made of steel, or occasionally copper or brass, and a larger head often made of plastic. The sharpened body penetrates the material, while the larger head provides a driving surface. In machines and engineering, pins are commonly used as pivots, hinges, shafts, jigs, and fixtures to locate or hold Types of pins – Cotter Pin/Split Pin – Dowel Pin parts.

PINS-Split/Cotter A split pin, also known as a cotter pin or cotter key, is a metal fastener with two tines that are bent during installation, similar to a staple or rivet. A split pin is secured after passing through holes in the parts to be attached, by spreading the ends

PINS- Dowels solid cylindrical rod, usually made of wood, plastic, or metal. used in numerous, diverse applications: – – – axles in toys, structural reinforcements in cabinet making, furniture shelf supports moveable game pieces (i. e. , pegs) supports for hanging items such as clothing, key rings, tools, toilet roll dispensers and picture frames – to precisely align two objects

KEYS a machine element used to connect a rotating machine element to a shaft. prevents relative rotation between the two parts and enables torque transmission. for a key to function, the shaft and rotating machine element must have a keyway, also known as a keyseat, which is a slot or pocket the key fits in. The whole system is called a keyed joint.

RIVETS permanent mechanical fastener consists of a smooth cylindrical shaft with a head on one end. on installation the rivet is placed in a punched or drilled hole, and the tail is upset, or bucked (i. e. , deformed), so that it expands to about 1. 5 times the original shaft diameter, holding the rivet in place. Because there is effectively a head on each end of an installed rivet, it can support tension loads (loads parallel to the axis of the shaft); however, it is much more capable of supporting shear loads (loads perpendicular to the axis of the shaft). Bolts and screws are better suited for tension applications.