Chapter 11: Threads and Fasteners

Agenda

Why they are important

Creating Threads and blocks to re-use them

Creating Hexagonal Bolt and Nut shapes

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But First…TEST 2 !!! Next Saturday 1-2PM

Will Cover: Chapters 6 -10Sectional Views

Auxiliary Views

Dimensioning

Tolerancing

Geometric Tolerancing

Open Book and NotesYou may be asked to do a hand sketch

• Practice Visualizing aux views…see examples

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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

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Design Center Demo

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Pre-constructed blocks

Choose Fasteners, US or

Metric

Place, resize, etc

3 ways to represent threads

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Threads—terms and specs

Pitch in threads/mm

or threads/inch

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Preferred Metric Threads

Thread specs for English Units (Inches)

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Detail Thread (Inches)

Creating wblocks

After drawing the object you want to re-useSelect 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)

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MM thread

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

DETLMM

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Internal Thread explode then erase, Hatch ANSI 31

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Schematic Thread

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Metric Thread, scale inch by 20

Save as

SCHMMM

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InternalSchematicThread

Scale by 36/20=1.8

Section using Hash ANSI31

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Simplified thread

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Draw hatch before hidden lines

Ortho & SecViews

Internal Threads

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Bolts, Nuts, Screws, Studs

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Nuts and Bolts

Hex Head Bolts HEXHEAD-10mm.dwgDistance across flats should be 1.5D

D=major diameter of the thread

Head thickness should be 0.67D

Finishing Nuts FNUTHEX-10mm.dwgThickness = .88D

Locking Nuts LNUTHEX-10mm.dwgThickness = 0.5D

Insert and scale to Major Diameter of thread

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Sample Problem 11-1: Threaded hole depth

Pilot hole depth

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SP11-2: Length of bolt

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