1. Fasteners, Welds, and Working Drawings
Mainly:
Chapters 10 (focus through Sec 19)
and Chapter 11 (focus on Sec 1 through 4)
Read Chapter 12
WILL NOT include drawing of fasteners such as Step by Step on pages 403, 409, 410, 417
Special thanks to Dr. Huifu Luo for his contributions to this material.

2. Threaded Fasteners External thread Used to hold parts together
Used to adjustment parts with reference to one another
Used to transmit power
Standards for form, size, pitch combinations set up by:
ANSI American National Standards Institute (Unified Thread Series – Inches)
ISO International Standards Institute (metric)
External thread
Internal thread

3. Screw Thread Terminology see page 397
Fig. 4(b) in text, flips the naming convention for the Root and Crest of an internal thread. We will use the convention shown here.

4. THREAD TERMINOLOGY Major diameter Minor diameter
The largest diameter on
an internal or external thread.
Major diameter
The smallest diameter on
an internal or external thread.
Minor diameter
External Thread
Internal Thread
Major dia.
Major dia.
Minor dia.
Minor dia.
Slide 4

5. External Thread Internal Thread
COMPARISON OF MINOR and MAJOR DIAMETER REGARDING THREAD CUTTING
External Thread
Internal Thread
Minor Dia.
Major Dia.
Slide 5

6. THREAD TERMINOLOGY Crest Root Thread angle The peak edge of a thread.
The bottom of the thread cut into a cylindrical body.
Root
Thread angle
The angle between threads faces.
External Thread
Internal Thread
Thread angle
Crest
Root
Root
Crest
Slide 6

7. THREAD TERMINOLOGY Right-hand thread Left-hand thread
Thread that will assemble when turned clockwise.
All threads considered right-handed unless specified otherwise.
Right-hand thread
Left-hand
thread
Thread that will assemble when turned counter-clockwise.
Noted with an LH
Turnbuckle use RH and LH thread at each end to double displacement.
Slide 7

8. THREAD TERMINOLOGY Pitch Lead
The distance from point on one thread to the same point on the next thread. For Example: between crests of threads.
Pitch
The distance a screw will advance when turned 360o. For a single thread L=P
Lead
Internal Thread
External Thread
Pitch
Pitch
Slide 8

9. Multiple Threads Starts Lead Indicates it is a Multiple Thread.
No Start Notation
(3 Starts)
(2 Starts)
Indicates it is a Multiple Thread.
New terminology so instead of DBL for double thread it is (2 Starts)
Triple thread would be indicated by (3 Starts)
Starts
In multiple thread Lead  Pitch
Lead for (3 Starts) = 3 times the pitch
Lead
Multiple Threads
Slide 9

10. THREAD CUTTING Tap Die Used to cut Internal threads
Read Section 9 on page 413
Especially see the Tip on top of page 414
Used to cut Internal threads
Internal threads denoted by the letter B in thread notes.
Tap
Used to cut External threads.
External thread denoted by the letter A in thread notes
Die
Threading Die
Tap
Slide 10

11. THREAD TERMINOLOGY Thread Form
Form is the profile shape of the thread.
See Pages 398 and 399
Thread Form
American National
Unified
Metric
ACME
Knuckle
Buttress
Most Common
High Stress along one-direction of thread axis such as tubular features screwed together
Loose fitting such as
electric sockets and light bulbs
similar to Unified
Rapid traversing movement
such as screw jacks and vice screws
Slide 11

12. Thread Series See Table 1 on page 400
Detail of Shape and Number of threads per inch
PITCH is a distance calculated. P=1 inch divided by the threads per inch value
Numerous Series
UN general stands for Unified National
UNC Coarse thread for general purpose holding.
UNF Fine thread used extensively in aircraft and auto construction
UNEF Extra Fine thread
UNR basic series but rounded the root more than the UN ones. A rounded root improves the fatigue strength.
Only found on external threads.
UNJ a newer specification – the root is rounded even more.
Results in a larger minor diameter.
Found on both external and internal threads.
Constant-pitch
8UN All diameters have 8 threads per inch. Used on bolts for high pressure pipe applications.
12UN All diameters have 12 thds/in. Used in boiler work and in machine construction.
16UN All diameters have 16 thds/in. Used on adjusting collars and other applications where thread must have fine adjustment regardless of diameter.

13. Thread symbols FOR Thread Representations see section 2-4 PAGES will need to recognize the 3 types OF SYMBOLS Used for Thread rEPresentatioNS but will not need to create drawings/sketches of them
Detailed Thread Representation
Used when diameter of thread is 1” or larger on the plotted drawing.
Use when it is important to show the thread and imply its function.

14. Simplified & Schematic THREAD Representations
Imply depth of thread with hidden lines for simplified representation
Use alternating long thin & short thick lines to represent root & crest lines in schematic representation
Simplified representation is called “Cosmetic Thread” in Solidworks

15. AutoCAD Blocks for Fasteners
Found in the directory Design Center>Fasteners- US.dwg
Mostly simplified representations.
Slide 15

16. Bolts Screws Head on one end Passes through clearance holes
Threaded on other end for the nut
Length measured from bearing surface
Threaded length is based on diameter
See Appendix 17 and others
Threaded Length
FASTENER LENGTH
Screws
Greater threaded length
Pass through clearance hole then other part is threaded in order to act like a nut.
Many types
Cap
Machine
Set
See Appendix 18 and others,
Details of lengths and other specific dimensions found there. Vary for each type.
Threaded Length
FASTENER LENGTH
Slide 16

17. Thread Notes – INCH THREADS
See Figure 16 on page 405
INTERNAL THREAD

18. Thread Notes – INCHES (continued)
EXTERNAL THREAD
Shown with Schematic Thread Symbol Representation

19. Metric Thread Notes INTERNAL EXTERNAL
Drill(Minor) Diameter (mm)
Drill Depth (mm)
INTERNAL J
8 x
M J 10 x 2
Metric Symbol
Thread Form
Thread (Major) Diameter (mm)
Thread Depth
Pitch (mm) J
Drill Depth
Thread Depth (mm) 55
EXTERNAL
Metric
Tolerance Class Designation
Major Diameter (mm)
Pitch (mm)
Reminder that metric is case-sensitive...
in tolerances then lower case letters refer to shafts and upper case letters refer to holes

20. WELDING Representations Chapter 11 Starting on page 438 Focus sections 1-4
Most common is FILLET which has the triangle symbol
See Figure 3 on page 442, Figures 4 and 5 on page 443

21. WELDING SYMBOL See Fig. 8 pg 444
Field Weld Symbol
Weld TYPE Symbol goes here
LENGTH - PITCH
SIZE X
XX - XXX
Weld All Around
means “Welder’s Choice” so it wouldn’t necessarily have all the other specifications
Placement of Symbol above or below line indicates the location of weld
Opposite Side
Same Side

22. Weld Placement (continued)
Symbol on BOTH SIDES
Both Sides
3/8”
4” – 9”
Weld Placement (continued)
Weld Length
Length
Pitch
Size
Length
Pitch
Pitch
Unequal
Equal Spacing
Staggered
See Fig 14b pg 446

23. BOM stands for Bill of Materials.
WORKING Drawings
Read through Chapter 12 starting page 464
Working drawings provide all information needed to manufacture and assemble a product or system.
Detail drawings show all necessary views, dimensions and notes needed to manufacture a part.
Assembly drawings show enough information to assemble parts.
A parts list identifies item number, part name, material, quantity and sometimes a company part number or other information.
BOM stands for Bill of Materials.
To get Bill of Materials in SolidWorks use the pull- down menu of INSERT>TABLES>Bill of Materials