Threads and Fasteners. EML 2023 Computer Aided Design Thread Terminology.
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Transcript of Threads and Fasteners. EML 2023 Computer Aided Design Thread Terminology.
Threads and Fasteners
EML 2023Computer Aided Design
Thread Terminology
EML 2023Computer Aided Design
Thread Callouts - Metric
(mm)
(mm)
(mm)
EML 2023Computer Aided Design
Thread Callouts – ANSI Unified
(in) UNC – Unified National CourseUNF – Unified National FineUNEF – Unified National Extra FineUN – Unified National
1 – loosest fit2 – normal fit3 – most exact fit
B represents internal thread
EML 2023Computer Aided Design
Thread Callouts – ANSI Unified
(in)Assumes course threads with a nominal fit (2).
EML 2023Computer Aided Design
EML 2023Computer Aided Design
EML 2023Computer Aided Design
EML 2023Computer Aided Design
Goal:• connect the top part to the bottom part using a .75” long #10-24 cap screw
which has a head taper of 82˚
EML 2023Computer Aided Design
Steps:• buy the screw• drill a countersunk hole without threads into the top part• drill a threaded hole in the bottom part
EML 2023Computer Aided Design
2 things to know
• if you tap a hole– the thread length should be at least twice the
diameter of the hole
• if you use a bolt to connect some bodies– the bolt should extend beyond the nut by at least two
thread pitches
EML 2023Computer Aided Design
EML 2023Computer Aided Design
Was able to download a SolidWorks part file of this cap screw.
EML 2023Computer Aided Design
Use ‘hole wizard’ to place a tapered hole, through all, for a #10 flat head screw with an 82˚ head taper.
Note that the major diameter of a #10 screw is 0.19” so we have clearance.
EML 2023Computer Aided Design
Use ‘hole wizard’ to place a tapped hole for a #10-24 screw.I selected a hole depth of 0.51” and a threaded depth of 0.38” (typically there should be at least 2 dia. of thread, i.e. at least 0.38” of thread).
This is the ‘default’ drawing after inserting dimensions from part file.
EML 2023Computer Aided Design
This is the ‘default’ drawing after inserting dimensions from part file.
delete this one
hide this one
Add the hole callout.
EML 2023Computer Aided Design
EML 2023Computer Aided Design
EML 2023Computer Aided Design
Design Library
• Tools -> Add in -> SolidWorks Toolbox
SolidWorks Toolbox Browser
EML 2023Computer Aided Design
Assembly with washers
Select a 3/8-24 bolt to connect the parts.
EML 2023Computer Aided Design
Assembly with washers and nut
EML 2023Computer Aided Design
Determining Bolt Length
EML 2023Computer Aided Design
Bolt length calculation
Bolt must be 1.92” long plus the distance of 2 extra pitches.
The bolt has 24 threads per inch. Two extra pitches will require an extra 1/12” of an inch.
Total minimum length is 1.92+0.083 = 2.003” .
Find the next longest available bolt.
EML 2023Computer Aided Design
Smart Fasteners
EML 2023Computer Aided Design
2 things to remember
• if you tap a hole– the thread length should be at least twice the
diameter of the hole
• if you use a bolt to connect some bodies– the bolt should extend beyond the nut by at least two
thread pitches
