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Fasteners

Fasteners. Mr. Lombardi. Fasteners. There are many different types of fasteners. Screws, Nuts, Bolts, etc. Each one performs specific task best accomplished by that specific fastener. Screws. A headed threaded fastener that is designed to be used by forming its own threads. . Bolts.

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Fasteners

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  1. Fasteners Mr. Lombardi

  2. Fasteners • There are many different types of fasteners. • Screws, Nuts, Bolts, etc. • Each one performs specific task best accomplished by that specific fastener.

  3. Screws • A headed threaded fastener that is designed to be used by forming its own threads.

  4. Bolts • A bolt is the term used for a headed fastener having external threads that meet an exacting, uniform bolt thread specification

  5. Nuts • A nut is a type of hardware fastener with a threaded hole. • Along with a bolt, nuts are designed to capture and fasten objects together.

  6. Cotter Pin • A metal fastener with two tines that are bent during installation, similar to a staple or rivet

  7. Retaining Ring • A small circular steel ring, often resembling the letter "C," that is usually inserted into a slot in a pivot pin to hold the pin in a specified position.

  8. Wing Nuts / Thumb Screws • A nut that can be tightened or removed without tools by turning it with fingers

  9. Classification • There are 7 descriptors for every bolt. • Material • Diameter • Pitch/Thread • Head Shape • Finish • Class • Grade

  10. Material • Steel • Stainless Steel • Brass • Etc.

  11. Diameter • T – Thread Diameter • R – Root Diameter (minor) • S – Shank Diameter

  12. Thread / Pitch • Measured in TPI (threads per inch)

  13. Pitch • Thread Pitch is measured with a special gauge

  14. Correct Pitch Gauge

  15. Incorrect Pitch Gauge

  16. Class • Class 1 = Loose • Class 2 = Free • Class 3 = Medium • Class 4 = Close • Most are class 2. 3 is for precision assembly, and 4 is used for things like lathe lead screws and measuring instruments.

  17. Head Shape • Many, many shapes and sizes

  18. Hardware Grade • The grade tells the strength of the fastener. • Nuts and Bolts must be the SAME grade.

  19. Grades (US) • Grade 2 – 74,000psi • Grade 5 – 120,000psi • Grade 8 – 150,000psi

  20. Grade 2 • Zinc plated low carbon steel. Best for general hardware use where high strength is not required.

  21. Grade 5 • Made from medium carbon steel, tempered and zinc plated. Best for automotive use and other areas where higher strength is desired.

  22. Grade 8 • Made from medium carbon alloy steel, tempered, and zinc plated. Best suited for applications where high strength and hardness is required.

  23. Grades (Metric) • Grade 8.8 • Grade 10.9

  24. Grade8.8 • Made from medium carbon steel and zinc plated. Best for general hardware use where high strength is not required. Standard metric thread pitches.

  25. Grade 10.9 • Made from alloy steel quenched, tempered, and zinc plated. Best for automotive use and other areas where high strength is needed.

  26. Bolt Identification

  27. Metric Bolt Identification

  28. Common Nuts L to R: Wing, hex, hex flange, and flanged weld (for stud welding) nuts.

  29. More Common Nuts L to R: Slotted, square, T, cap (or acorn), nylon locking, and castellated nuts

  30. Washers • Four Common Types • Flat • Split • Toothed • Insulating

  31. Common Washers

  32. Torque To Yield Bolts (TTY) • They are tightened (torqued) until they just begin to stretch • This provides a very consistent clamping load and helps keep an even sealing pressure for the items being fastened

  33. Torque to Yield bolts require special procedures • Tighten to the specified torque • Continue to turn the fastener just enough to cause it to begin to stretch • This will be specified in degrees of rotation

  34. Torque Angle Gauge

  35. Torque to Yield Graph

  36. The End

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