Lesson Notes By Weeks and Term v4 - SHS 3
Manufacturing tools and equipment
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Manufacturing tools and equipment
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Subject: Manufacturing Engineering
Class: SHS 3
Term: 1st Term
Week: 8
Grade code: 1.3.1.LI.2
Strand code: 3
Sub-strand code: 1
Content standard code: 1.3.1.CS.2
Indicator code: 1.3.1.LI.2
Theme: Manufacturing tools, equipment and processes
Subtheme: Manufacturing tools and equipment
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In every workshop, from the local carpenter at Agbogbloshie making furniture, to the mechanic at Suame Magazine in Kumasi rebuilding an engine, to the large-scale factory at Tema producing parts, one thing is constant: the need for precision. Accuracy is the difference between a part that fits perfectly and one that is useless. If a door is not measured correctly, it will not close. If a piston is not the exact right size, an engine will fail. Today, we will learn about the special tools, called gauges, that engineers and technicians use to measure workpieces with the high degree of accuracy required in manufacturing.
In manufacturing, we move beyond the simple tape measure used in sewing or basic carpentry. We need tools that can measure fractions of a millimetre. These precision tools are broadly called gauges. A. Measuring Tools for Length, Diameter, Depth, and Height Steel Rule / Steel Scale Description: A flat, straight piece of steel marked with graduated units (usually millimetres and centimetres on one edge, and inches on the other). Function: Used for making linear measurements where high precision is not the primary requirement. It is the most basic measuring tool in the workshop. How to Use: Align the 'zero' mark of the rule with one edge of the object being measured. Ensure the rule is parallel to the length you are measuring. Read the measurement on the scale that aligns with the other edge of the object. Avoid parallax error by looking at the scale directly from above. Precision: Typically to the nearest 0.5 mm. Vernier Calliper Description: A highly accurate measuring instrument with two jaws (one fixed, one sliding) and two scales: a main scale (like a ruler) and a sliding vernier scale. It can measure external dimensions, internal dimensions, and depth. Main Parts: Outside Jaws: For measuring external dimensions (e.g., the diameter of a pipe). Inside Jaws: For measuring internal dimensions (e.g., the inside diameter of a pipe). Depth Rod: A thin rod that slides out from the end to measure depths of holes. Main Scale: Marked in mm. Vernier Scale: The sliding scale with 10, 20 or 50 divisions. Thumb Screw/Slider: Used to move the sliding jaw. Locking Screw: To lock the sliding jaw in place for an accurate reading. Precision: Typically 0.02 mm or 0.05 mm. How to Read a Vernier Calliper (0.02 mm precision): Take the Main Scale Reading: Close the jaws on the workpiece. Look at the 'zero' mark on the vernier (sliding) scale. Read the last full millimetre mark on the main scale that is to the left of the vernier scale's zero. Take the Vernier Scale Reading: Look closely at the vernier scale divisions. Find the *one* line on the vernier scale that aligns perfectly with *any* line on the main scale. Calculate the Final Measurement: Multiply the coinciding vernier scale number by the precision of the calliper (e.g., 0.02 mm). Add this value to the main scale reading.