Sections Threaded Fasteners and power screws Rivets Springs Sliding Bearings Rolling-Element Bearings Spur Gears Helical Bevel and worm gears Threaded Fasteners and Power screws Classes of fasteners They may be classified into two broad categories: Removable and Permanent Removable Fasteners are defined as those that can be easily removed with hand tools and without damaging any parts. Ordinary nuts and bolts are ty pical examples. Permanent Fasteners are those that are insta lled so as to remain permanently in place; they would not be removed for routine maintenance work. Such as rivets Advantages of threaded fasteners Ease of assembly Ease of disassembly Can be accomplished with re lative ease by unskilled workers using minimum of special tooling and in a relatively short time Simple technology. Easily inspected Large products can be shipped and assembled at the customer site Replace worn components or to make adjustments. Types of Threaded Fasteners 1. Screws A screw is an external threaded fastener that is generally assembled into a blind threaded hole Screws are by far the most common types screws are intended for screwing into tapped holes. 2. Bolt and nut a bolt is an externally threaded fastener that is inserted through holes in the parts and screwed into a nut on the opposite side A nut is an internally threaded fastener having standard threads that match those on bolts of the same diameter, pitch, and thread form 3. Stud and nut A stud is threaded on both ends and is usually screwed permanently into a tapped hole Threads on the two ends may or may not be identical 4. Threaded rod and nuta threaded rod is the least common ty pe It is an external threaded fastener, but without the usual head possessed by a boltSections • Threaded Fasteners and Power Screws • Rivets • Springs • Sliding Bearings • Rolling-Element Bearings • Spur Gears • Helical, Bevel, and Worm Gears Threaded Fasteners and Power Screws Classes of Fasteners They may be classified into two broad categories: Removable and Permanent. Removable Fasteners are defined as those that can be easily removed with hand tools and without damaging any parts. Ordinary nuts and bolts are typical examples. Permanent Fasteners are those that are installed so as to remain permanently in place; they would not be removed for routine maintenance work. Such as Rivets. Advantages of threaded fasteners: Ease of assembly Ease of disassembly Can be accomplished with relative ease by unskilled workers using minimum of special tooling and in a relatively short time. Simple technology. Easily inspected. Large products can be shipped and assembled at the customer site. Replace worn components or to make adjustments. Types of Threaded Fasteners 1.Screws A screw is an external threaded fastener that is generally assembled into a blind threaded hole. Screws are by far the most common types. screws are intended for screwing into tapped holes. 2. Bolt and nut A bolt is an externally threaded fastener that is inserted through holes in the parts and screwed into a nut on the opposite side. A nut is an internally threaded fastener having standard threads that match those on bolts of the same diameter, pitch, and thread form. 3. Stud and nut A stud is threaded on both ends and is usually screwed permanently into a tapped hole. Threads on the two ends may or may not be identical. 4. Threaded rod and nutA threaded rod is the least common type. It is an external threaded fastener, but without the usual head possessed by a bolt