Chapter 11: Threads and Fasteners

Agenda Why they are important Creating Threads and blocks to re-use them Creating Hexagonal Bolt and Nut shapes 2

But First…TEST 2!!! Next Saturday 1-2PM Will Cover: Chapters Sectional Views Auxiliary Views Dimensioning Tolerancing Geometric Tolerancing Open Book and Notes You may be asked to do a hand sketch Practice Visualizing aux views…see examples 3

4 Sample Auxiliary View Problems

Threads and Fasteners Most mechanical objects need to be held together DesignCenter choices are somewhat limited More flexibility and better clarity by making our own and saving for later use We’ll use them next week: working drawings 5

Design Center Demo 6 Pre-constructed blocks Choose Fasteners, US or Metric Place, resize, etc

3 ways to represent threads 7

Threads— terms and specs Pitch in threads/mm or threads/inch 8 Preferred Metric Threads

Thread specs for English Units (Inches) 9

10 Detail Thread (Inches)

Creating wblocks After drawing the object you want to re-use Select the object Type “wblock” Choose a filename reflecting it’s content: DETLIN-1in And a place to store it (myDocs, Desktop, USB) Then you can choose Insert>Block, find the file, and insert (rotating or scaling first as needed) 11

MM thread Or try scaling the inch thread by 20 and saving as a new wblock DETLMM 12

Internal Thread explode then erase, Hatch ANSI 31 13

Schematic Thread 14

Metric Thread, scale inch by 20 Save as SCHMMM 15

Internal Schematic Thread Scale by 36/20=1.8 Section using Hash ANSI31 16

Simplified thread 17 Draw hatch before hidden lines

Ortho & Sec Views Internal Threads 18

Bolts, Nuts, Screws, Studs 19

Nuts and Bolts Hex Head Bolts HEXHEAD-10mm.dwg Distance across flats should be 1.5D D=major diameter of the thread Head thickness should be 0.67D Finishing Nuts FNUTHEX-10mm.dwg Thickness =.88D Locking Nuts LNUTHEX-10mm.dwg Thickness = 0.5D Insert and scale to Major Diameter of thread 20

Sample Problem 11-1: Threaded hole depth Pilot hole depth 21

SP11-2: Length of bolt 22