🔍 Key Concepts

• Different thread forms used in fasteners and power screws • Typical included angles for common thread types (e.g., 29°, 55°, 60°) • How the shape of the sides (square vs. slanted) affects the thread name and use

💭 Think About

• Look at the included angle marked 29° in the illustration and think which thread form is known for that angle • Compare the flatness of the crest and root and the sloping sides with what you know about square, Whitworth, and common machine screw threads • Ask yourself which thread form is often used for power transmission (lead screws, vises, jacks) rather than just fastening

✅ Before You Answer

• Match the 29° included angle to the correct standard thread form from your study materials • Confirm whether square threads have any included angle at all between their sides • Verify which named thread form (Whitworth, Acme, Standard) is specifically associated with slanted sides and flat crest/root used on lead screws