threads, fasteners, and springs chapter 11. 2 technical drawing 13 th edition giesecke, mitchell,...
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Threads, Fasteners, and Springs
Chapter 11
2Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Objectives
• Define and label the parts of a screw thread
• Identify various screw thread forms• Draw detailed, schematic, and
simplified threads• Define typical thread specifications
3Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Objectives (cont.)
• Identify various fasteners and describe their use
• Draw various screw head types• Draw springs
4Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Understanding Threads and Fasteners• There are three basic applications
for screw threads:• To hold parts together• To provide for adjustment between
parts• To transmit power
5Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Terms
6Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Terms
• Screw thread – a ridge of uniform section in the form of a helix on the external or internal surface of a cylinder
• External thread – a thread on the outside of a member
• Internal thread – a thread on the inside of a member
7Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Terms
• Major diameter – the largest diameter of a screw thread
• Minor diameter – the smallest diameter of a screw thread
8Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Screw Thread Terms
• Pitch – the distance from a point on a screw thread to a corresponding point on the next thread measured parallel to the axis• Pitch (P) equals 1 divided by the
number of threads per inch
9Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Screw Thread Terms
• Pitch diameter – the diameter of an imaginary cylinder passing through threads where the widths of the threads and the widths of the spaces would be equal
• Lead – the distance a screw thread advances axially in one turn
10Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Terms
• Angle of thread – the angle between the sides of the thread measured in a plane through the axis of the screw
• Crest – the top surface joining the two sides of a thread
• Root – the bottom surface joining the sides of two adjacent threads
11Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Terms
• Side – the surface of the thread that connects the crest with the root
• Axis of screw – the longitudinal centerline through the screw
• Depth of thread – the distance between the crest and the root of the thread measured normal to the axis
12Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Screw Thread Terms
• Form of thread – the cross section of thread cut by a plane containing the axis
• Series of thread – standard number of threads per inch for various diameters
13Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Forms
• Typical thread forms include:• Sharp-V thread (60 degrees)• American national thread• Unified thread• Unified extra fine thread series• Metric thread• Square thread• Acme thread
14Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Forms
• Typical thread forms (cont.)• Standard worm thread • Whitworth thread• Knuckle thread• Buttress thread
15Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Screw Thread Forms
16Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Thread Pitch
17Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Right-hand and Left-hand Threads
18Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Single and Multiple Threads• Single threads are composed of
one ridge and the lead is equal to the pitch
• Multiple threads are composed of two or more ridges running side by side
19Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Single and Multiple Threads
20Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Thread Fits
• ANSI has established 3 classes of fit:• Class 1 – when clearance between
mating parts is essential• Class 2 – high quality for the bulk of
interchangeable screw thread work• Class 3 – exceptionally high quality
recommended only when high cost of precision is warranted
21Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Thread Fits
• Some specialized metric thread applications are specified by:• Tolerance grade• Tolerance positions• Class• Length of engagement
22Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Methods for Drawing Thread• There are three methods of
representing screw threads on drawings:• Schematic• Simplified• Detailed
23Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Methods for Drawing Thread
24Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Methods for Drawing Thread
25Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Methods for Drawing Thread
26Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Thread Notes
• ASME/ANSI Y 14.6-2001 “Screw Thread Representations” is a standard for representing, specifying, and dimensioning screw threads on drawings• These same notes or symbols are
used in correspondence, in records, and in specifications for parts, taps, dies, tools, and gages
27Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Thread Notes
28Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Thread Notes
29Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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External Thread Symbols
30Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Internal Thread Symbols
31Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Detailed Representation
32Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Detailed Representation
33Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Use of Phantom Lines
34Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Threads in Assembly
35Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Pipe Thread Representation
36Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Bolts, Studs, and Screws
37Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Types of Screw Heads
38Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Tapped Holes
• The bottom of a drilled hole formed by the point of a twist drill is cone shaped
• The thread length is the length of full or perfect threads• The tap drill depth does not include
the cone point of the drill
39Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Tapped Holes
40Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Standard Bolts and Nuts
• Standard bolts and nuts have characteristics determined by:• Bolt types• Finish• Proportions• Threads• Thread lengths • Bolt lengths
41Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Specifications
• In specifying bolts, the following information must be covered in order:• Nominal size of bolt body• Thread specification or thread note• Length of bolt• Finish of bolt• Style of head• Name
42Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Locknuts and Locking Devices
43Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Standard Cap Screws
44Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Standard Machine Screws
45Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Standard Set Screws
46Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Standard Wood Screws
47Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Miscellaneous Fasteners
48Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Keys
• Keys are used to prevent movement between shafts and wheels, couplings, cranks, and similar machine parts attached to or supported by shafts
49Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Keys
50Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Machine Pins
• Machine pins include taper pins, straight pins, dowel pins, clevis pins, and cotter pins
51Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Rivets
• Rivets are permanent fasteners used to hold sheet metal or rolled steel together
52Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Springs
• A spring is a mechanical device designed to store energy when deflected and to return the equivalent amount of energy when released
• Springs are classified as:• Helical springs• Flat springs
53Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Helical Springs
• Helical springs have three types:• Compression springs• Extension springs• Torsion springs
54Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
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Helical Springs
55Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Compression Springs
56Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Extension Springs
57Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Torsion Springs
58Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
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Flat Springs