Lesson Notes By Weeks and Term v5 - Grade 11

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Draw conventional representations of screws.
• Draw simplified representations of nuts and bolts.
• Identify and draw keys and keyways.
• Apply correct dimensioning techniques.
• Understand the function of different fasteners.

Lesson summary

This week, we delve into the crucial world of fasteners and machine components. These are the "nuts and bolts" (literally!) that hold everything together in mechanical engineering. Understanding how to represent these elements accurately in technical drawings is paramount for clear communication between designers, engineers, and manufacturers.

Imagine designing a taxi rank shelter: without a solid grasp of fasteners and components, you wouldn't be able to specify how the steel beams connect, or how the roof panels attach.

Lesson notes

2. 1. Screws Screws are externally threaded fasteners designed to be inserted into a pre-tapped hole or to create their own mating thread. There are many types, each suited for specific applications.

Machine Screws: Used to fasten metal parts. They are typically threaded along their entire length. Common head types include pan, flat, round, and oval.

Wood Screws: Designed to fasten wood. They have a tapered shank and a sharp thread that cuts into the wood. Head types are similar to machine screws.

Set Screws: Used to prevent relative motion between two parts, typically a shaft and a collar or pulley. They are often headless and tightened with a wrench. Point styles include cup, cone, dog, and flat.

Self-tapping screws: These screws cut their own threads as they are driven into the material, eliminating the need for pre-drilled holes in some applications.

Conventional Representation of Screws: Instead of drawing the threads individually, we use conventional representations. These simplify the drawing process while still providing the necessary information.

External Threads: Represented by parallel lines running along the shank. One line is thick, and the other is thin. The thick line represents the crest (outer edge) of the thread, and the thin line represents the root (inner edge) of the thread.

Internal Threads: Shown as hidden lines in section views. Again, one line is thick and one is thin.

Head Types: Drawn according to their shape (e.g., pan head, flat head), using appropriate dimensions.