Question of the Day Who invented the zipper and what year was it invented? ANSWER: Whitcomb L. Judson, 1893 Lecture 22 - AutoCAD

What’s Coming Up? Today Tuesday Wednesday Thursday Fasteners & Welding Working Drawing Set Wednesday Measurements Lab Thursday Quiz on Fasteners and Welding Introduction to AutoDesk Inventor Lecture 22 - AutoCAD

Fasteners and Welding Objectives: Understand importance of fasteners, learn how to specify threaded fasteners and represent them in drawings and learn about other fastening methods. Understand basics of welding symbols Lecture 22 - AutoCAD

Topics For Today Importance of fastening Threaded fasteners Non-threaded fasteners Other machine elements Adhesives Welding Lecture 22 - AutoCAD

Importance of Fastening 50% of production time for the average item is spent on assembly/fastening. Fasteners are critical to product performance and reliability Choosing the proper fasteners is an important part of product design Lecture 22 - AutoCAD

Three Methods Commonly Used in Fastening Mechanical Fastening Bolts, rivets, keys, pins Paper clips, zippers, “Velcro” Bonding Welding, soldering, brazing, gluing Forming Sheet metal, plastic snaps parts Lecture 22 - AutoCAD

Threaded Fasteners – Terminology External Threads Lecture 22 - AutoCAD

Threaded Fasteners – Terminology Internal threads Threads inside a hole Made by drill & tap: drill smooth hole make threads with a tap Lecture 22 - AutoCAD

Threaded Fasteners – Terminology Bolt - head on one end, threads on other end, used with a nut Stud - rod threaded at both ends Cap screw - head on one end, threads on other end, NOT used with a nut Machine screw - similar to cap screw but smaller Set screw - used to prevent 2 rotating parts from moving separately Lecture 22 - AutoCAD

Threaded Fasteners – Specification Example of a typical thread specification (in inches) .5 - 28 UNC - 3 B .5 - major diameter of .5 inches 28 - 28 threads per inch UN - form Unified (i.e. shape of the thread) C - series (C means coarse), F (fine), EF (extra fine) There are several thread forms. UN is common. Lecture 22 - AutoCAD

Threaded Fasteners – Specification Continuation of example of a typical thread specification (in inches) .5 - 28 UNC - 3 B 3 - class of fit (3 is precise, 2 is normal, 1 is loose fit) B - internal thread (A is for external) Lecture 22 - AutoCAD

Threaded Fasteners – Specification Example of a typical metric thread specification M6 x 1 - 4H5H M - indicates thread form is metric 6 - major diameter in millimeters 1 - pitch in millimeters 4H5H - tolerance (capital letters for internal thread, lower case for external thread) Lecture 22 - AutoCAD

Representing External Threads Options for representing external threads in a drawing Schematic 2. 1. End View Detailed Lecture 22 - AutoCAD

Representing Internal Threads Options for representing internal threads Schematic (in section) Detailed (in section) Unsectioned End View Lecture 22 - AutoCAD

Non-Threaded Fasteners Rivets Pins Keys Retaining rings Locking washers Lecture 22 - AutoCAD

Other Machine Elements Springs Bushings Bearings (See references for more details) Lecture 22 - AutoCAD

Adhesives Used to join thin or dissimilar materials Seal a joint as well as bond it Can be used to coat threads and prevent loosening Lecture 22 - AutoCAD

Thermal Fastening Soldering - solder (filler) melts but parts to be joined remain at low temperature Brazing - filler is melted, and parts to be joined are heated but do not melt. Can be used to join dissimilar metals Welding - parts to be joined and filler (if any) are melted, pressed together and then cool. (See Section 10.9 in FGC) Lecture 22 - AutoCAD

Welding Symbol Reference Line Leader and arrow Basic weld symbol (location & depth of weld) Finish symbol Weld symbol Dimensions Supplementary symbols Tail and specifications Lecture 22 - AutoCAD

Welding Symbol Leader Reference Line Tail Lecture 22 - AutoCAD

Welding Symbol – Example Fillet Weld Weld around Opposite side Arrow side Lecture 22 - AutoCAD

Welding Symbol Below reference line describes the ARROW side of the weld Above the line describes the OTHER side Joint described by symbol (fillet, square) Numbers by symbol indicate size Circle at joint specifies weld around Lecture 22 - AutoCAD

References Threaded and Other Fasteners Welding BTG Chapter 9, Appendices A24 – A42 Welding BTG Appendix B.25 Lecture 22 - AutoCAD

Assignments Dwg 43 – FB-1D – Fasteners Answer questions about fasteners using the tables in the book. Due Today Dwg 44 – FD-3B – Welding Symbology Add notes to the Welding Symbols as needed to make them match the schematic Due Tuesday Dwg 45 – Working Drawing Set A Handout will be provided in class Lecture 22 - AutoCAD