# Lesson Notes By Weeks and Term - Senior Secondary 3

TERM – 1ST TERM

WEEK FOUR

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Technical Drawing

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) Discuss the concept, screw thread.

II.) Identify and describe the types of screw threads.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher explains the concept, screw thread and identify the various types of screw thread. Students listens attentively to the teacher STEP 2 EXPLANATION Teacher guide students to draw out the various types of screw thread. Students exhibit attentiveness and active engagement STEP 3 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

A screw thread is a helical ridge or groove wrapped around a cylindrical or conical surface. It's designed to engage with a mating thread, such as a nut or another screw, to convert rotational motion into linear motion or vice versa. Screw threads are widely used in various applications for fastening, adjusting, and transmitting motion and force.

1. V-shape threads: Also known as "V threads," they have a triangular cross-section and are commonly used in bolts, nuts, and screws due to their self-locking nature.

2. Square threads: These have a square cross-section and are often found in high-load applications where efficiency and power transmission are critical, like jackscrews and vises.

3. Acme threads: Acme threads are trapezoidal in shape and commonly used in lead screws and power screws for translating rotational motion into linear motion.

4. Buttress threads: Featuring one flat and one angled flank, buttress threads are suitable for applications where a large axial force is present, like in vise screws and the lead screws of heavy-duty machinery.

5. Worm threads: These have a cylindrical shape and resemble a screw thread wrapped around a cylindrical core. They're commonly used in worm gears for power transmission.

EVALUATION: 1. Identify and sketch the type of screw thread below:

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively