BASIC TECH JSS1 SECOND TERM LESSON NOTE
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BASIC TECH JSS1 SECOND TERM LESSON NOTE
DRAWING INSTRUMENTS AND MATERIALS
CONTENT
1. Definition of Technical Drawing
2. Drawing Instrument and Materials
Definition of Technical Drawing
Technical drawing is a universal language used for communication among technical
people. A good and accurate drawing can only be made through constant practice
with the aid of drawing instruments and materials. Technical drawing can also be
defined as a language of communication making use of lines, curves, symbols and
conventions.
Drawing Instrument and Materials
Drawing instruments and materials for technical drawing are:
1. Drawing board
2. Tee square
3. Sets squares
4. Protractor
5. Compasses
6. Dividers
7. Drawing paper clips
8. Scale rules
9. French curves
10. Metric rules
11. Drawing paper
12. Drawing pencils
13. Eraser
14. Sharpener or blade
15. Flexi curves
16. Scale rule
17. Metal clip
18. Lettering set
BASIC TECH JSS1 SECOND TERM LESSON NOTE
EVALUATION
1. Define technical drawing.
2. List 10 instruments for drawing in technical drawing.
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USES OF DRAWING INSTRUMENTS AND MATERIALS
CONTENT
1. Uses of Drawing Instruments and Materials
Uses of Drawing Instruments and Materials
(i) A drawing board is the wooden platform on which the drawing paper is placed
before the drawing starts. The two main types are (a) full imperial size which is
812 × 585mm (b) half imperial (585 × 452mm) size.
(ii) Tee square is used for drawing horizontal or parallel lines in conjunction with
drawing board.
(iii) Drawing pencils are of different grades used for general drawing, lettering or
freehand sketching and technical or engineering drawing. We have B, 2B, 3B, 4B up
to 8B and H, 2H, 3H, 4 H up to 8H pencils.
(iv) A Compass is used for drawing circles and arcs.
(v) A Divider is used for transferring measurement from the metric rule to the drawing.
(vi) Set Squares are used to draw vertical or diagonal lines.
(vii) Drawing Papers are best held on the boards with the aid of clips or adhesive tape.
(viii) The Protractor is used for measuring and marking out angles.
(ix) Scale Rules are used to produce reduced or enlarged sizes of objects.
(x) A Metric Rule is used for drawing various types of curves.
(xi) Drawing paper is the paper on which the drawing is produced.
The common paper sizes are: A0: 841 * 1189
A1: 594 * 841
A2: 420 * 594
A3: 297 * 420
A4: 210 * 297
(xii) Eraser: A good eraser must erase cleanly without picking or tearing the
surface of the paper.
BASIC TECH JSS1 SECOND TERM LESSON NOTE
EVALUATION
1. What is Technical Drawing?
2. Name four types of drawing instruments.
BASIC TECHNIQUES FOR HANDLING AND CARING FOR DRAWING
INSTRUMENTS AND MATERIALS
CONTENT
Basic Techniques of Handling;
1. Drawing Board
2. Tee-Square
3. Set-Square, Scale Rules, Protractor and French Curves
4. Pair of Compasses or Dividers
5. Other Instruments
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Introduction
We need to take care of our drawing instruments in order to prolong their service life.
Basic Techniques of Handling Drawing Board
1. Do not use pins for fastening your paper to the board, use tapes or clips.
2. Do not use blade or knife to cut something on the surface of your drawing
board.
3. Always cover the surface with cardboard or thick paper.
4. Keep the drawing board in a safe place when not in use.
BASIC TECH JSS1 SECOND TERM LESSON NOTE
Basic Techniques of Handling Tee-Square
1. Never use the tee-square as a walking stick or as a cane.
2. Do not use pen-knife or blade along the edge of the tee-square
3. Always hand your square when not in use.
4. Always keep your tee-square clean.
Basic Techniques of Handling Set-Square, Scale Rules, Protractor and French Curves
1. Do not use any sharp object such as razor blade or knife on their edges.
2. Keep them away from fire.
3. Always keep them in a safe place immediately after use to prevent leakage.
Basic Techniques of Handling Pair of Compasses or Dividers
1. When not in use, keep them away in a safe container.
2. Never use compasses or dividers as paper holders.
3. Do not use their needle points to punch holes.
Other Instruments
All other instruments should be kept in their packets after use. A cupboard should be
made available for complete storage of the drawing boards and all other instruments.
EVALUATION
1. Why do we need to take care of our drawing instrument?
2. How do we take care of tee-square?
3. What are the uses of (a) drawing board (b) tee-square (c) set-square
BASIC BOARD PRACTICE
CONTENT
1. Setting Drawing Paper on the Board
2. Sharpening of Drawing Pencils to Conical Point and Knife Edge
3. The Instruments Required for Good Board Practice
Setting Drawing Paper on the Board
Step 1: The drawing board is conveniently placed on the table with the paper on the
board, leaving equal size all rounds, with the Tee-square edge to the left hand side.
Step 2: Place the tee-square on the paper and gently move or slide the tee-square to
the top edge of the paper. Set the top edge of the paper parallel to the edge of the
tee-square with the stock of the tee-square firmly against the edge of the drawing
board on the left-hand side.
Step 3: Hold the paper with four pieces of adhesive tape or two metal clips to hold
the paper in position at four corners.
Step 4: Gently slide the tee-square down without moving the paper.
BASIC TECH JSS1 SECOND TERM LESSON NOTE
Sharpening of Drawing Pencils to Conical Point and Knife Edge
A well sharpened pencil is very essential to technical drawing. Pencils for lettering
and freehand sketching should be sharpened to a ‘conical point’ while those for
geometrical or engineering drawing should be sharpened to a ‘chisel point’.
All horizontal lines are drawn with the aid of tee-square. The set-square is used
sitting squarely on the tee-square to draw vertical lines.
BASIC TECH JSS1 SECOND TERM LESSON NOTE
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