Threads & Bolted Joints I: Thread Terminology and Designations
Watch the full series (recommended order):
• Threads, Power Screws, and Bolted Joints: ...
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Originally prepared for BRAE 421 at Cal Poly.
This series is intended to help students understand both the practical calculations and the mechanical reasoning behind threaded fasteners, power screws, preload, stiffness, and bolted joint failure criteria.
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In this video, we introduce thread terminology and thread designations used for fasteners and power screws.
We define the key dimensions of a thread, distinguish pitch from lead, distinguish thread angle from lead angle, and work through examples involving lead angle and tensile stress area.
We cover:
• Crest and root
• Major, minor/root, mean, and pitch diameters
• Pitch vs lead
• Single-start and multiple-start threads
• Thread angle vs lead angle
• Unified and metric thread designations
• Fine vs coarse threads
• Rounded-root threads
• Tensile stress area
• Square and Acme power screw threads
00:00 Intro
00:17 Thread profile terminology
02:37 Mean and pitch diameter
05:22 Pitch vs lead
06:59 Thread angle
07:58 Lead angle
10:37 Lead angle example
14:06 Tensile stress area and proof load
15:39 Tensile stress area example
17:51 Quiz
18:50 Thread designation
21:56 Fine thread pros and cons
24:11 Power screws
28:52 Square thread pros and cons
30:13 Intended learning outcomes
Note: This description was generated with AI assistance. If you notice anything incorrect or unclear, please leave a comment so it can be improved.