Dimensioning
18 Grade 8 Pre-Technical Studies questions on Dimensioning, with worked marking schemes. 18 questions are available on this topic in full.
Question 1
1 markWhich symbol is placed before a dimension figure to indicate that the feature is a diameter of a circle?
A. R
B. □
C. Ø
D. ∠
(1 mark)
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1 markA learner is dimensioning a working drawing and is unsure which line shows the actual size between two points. Which line carries the dimension figure between extension lines?
A. Border line
B. Hidden line
C. Dimension line
D. Centre line
(1 mark)
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4 marksA circle on a drawing has a diameter of 50 mm. (a) State the symbol and the complete dimension you would write for the circle. (2 marks) (b) Give two reasons why correct dimensioning is important in the manufacture of a product. (2 marks)
(4 marks)
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1 markA small circular hole is dimensioned as Ø8. This means the hole has a:
A. Depth of 8 mm
B. Area of 8 mm
C. Radius of 8 mm
D. Diameter of 8 mm
(1 mark)
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1 markA learner places dimension figures on a drawing so they can be read clearly. According to drawing conventions, where should the dimension figure be placed relative to the dimension line?
A. On the object outline only
B. Inside the arrowhead
C. Above and along the dimension line
D. Crossed out by the line
(1 mark)
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1 markA learner measures a rectangular metal plate as 120 mm long. On the drawing, the line with arrowheads at both ends that carries this measurement is called the:
A. Construction line
B. Dimension line
C. Projection line
D. Border line
(1 mark)
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1 markWhen dimensioning a drawing, the smallest dimensions should be placed:
A. Furthest from the object
B. In the title block
C. On the hidden lines
D. Nearest to the outline of the object
(1 mark)
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6 marksIn a technical drawing lesson, a learner has drawn a rectangle and now has to add dimensions to it. (a) State the purpose of dimensioning a technical drawing. (2 marks) (b) Name and briefly describe two types of lines used when dimensioning. (4 marks)
(6 marks)
Marking scheme
(a) The purpose of dimensioning is to indicate the actual sizes (measurements) of the object - such as length, width, height and the position of features - so that the object can be made accurately to the correct size from the drawing. (b) Two types of lines used in dimensioning: (i) Extension (projection) lines - thin lines drawn outward from the edges/points of the object being measured; they show the limits of the dimension and do not touch the outline. (ii) Dimension line - a thin line drawn between the extension lines, ending in arrowheads, on which the measurement (figure) is written to state the actual size. (Leader lines, used to point to a feature and add a note, are also acceptable.)
Question 9
1 markWhich of the following is the unit generally used for dimensioning engineering drawings in the Kenyan Pre-Technical workshop?
A. Centimetre (cm)
B. Millimetre (mm)
C. Kilometre (km)
D. Metre (m)
(1 mark)
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1 markA learner preparing a working drawing must show the size of each part clearly. In dimensioning, what is the purpose of the small arrowheads placed at the ends of a dimension line?
A. To show the weight of the object
B. To show exactly where the measurement begins and ends
C. To decorate the drawing
D. To indicate the colour of the part
(1 mark)
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Create a free account to see itQuestion 11
5 marksA learner is producing a working drawing of a rectangular metal bracket so that another learner can make it exactly to size.
(a) Explain why dimensioning is important on a working drawing. (2 marks)
(b) State THREE rules (conventions) the learner should follow when placing dimensions on the drawing. (3 marks)
(5 marks)
Marking scheme
(a) Dimensioning is important because it shows the exact sizes (length, width, thickness, diameters, etc.) of the object so that it can be manufactured accurately to the intended measurements without guessing; it clearly communicates measurement information to the person making the part. (2 marks) (b) Any THREE (1 mark each): Dimension lines should be thin/continuous lines with arrowheads touching the extension lines; figures (numbers) should be placed above and at the middle of the dimension line / readable from the bottom or right; extension (projection) lines should not touch the outline of the object but leave a small gap; each dimension should be given only once and not repeated; place dimensions outside the outline of the view where possible; use the same unit of measurement throughout.
Question 12
1 markThe arrowheads used at the ends of a dimension line should be drawn:
A. Narrow, filled and touching the extension lines
B. Wide and open, away from the lines
C. As dots
D. As small circles
(1 mark)
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1 markA good practice in dimensioning requires that a dimension figure be placed so that it can be read from:
A. The bottom and the right-hand side of the drawing
B. Any four sides equally
C. The top only
D. The left-hand side only
(1 mark)
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4 marksDistinguish between an extension line and a dimension line as used in technical drawing, and state how each is drawn. (4 marks)
(4 marks)
Marking scheme
Extension line (projection line): a thin line drawn from the feature outward to show the extent/limits of the dimension; it starts a small gap from the object outline (2 marks). Dimension line: a thin line drawn between the extension lines with arrowheads at both ends, carrying the dimension figure at its centre (2 marks).
Question 15
1 markThe letter 'R' placed before a dimension on a technical drawing indicates that the measurement is a:
A. Rectangle
B. Radius
C. Reference
D. Diameter
(1 mark)
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1 markWhich type of dimensioning gives the size of features one after another, each measured from the previous point?
A. Angular dimensioning
B. Chain dimensioning
C. Radial dimensioning
D. Datum dimensioning
(1 mark)
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1 markIn technical drawing, the two thin lines drawn outward from a feature to show the limits of a dimension are called:
A. Cutting plane lines
B. Centre lines
C. Extension lines
D. Hidden lines
(1 mark)
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5 marksA learner is dimensioning a drawing of a machine part. (a) Define the term dimensioning as used in technical drawing. (2 marks) (b) State three rules that should be followed when dimensioning a drawing. (3 marks)
(5 marks)
Marking scheme
(a) Dimensioning is the process of adding measurements (sizes) such as lengths, diameters and angles to a drawing to show the exact size and location of features (2 marks). (b) Any three: dimensions should be in millimetres; place dimensions outside the outline where possible; do not repeat/duplicate dimensions; place small dimensions nearest the object; arrowheads must touch the extension/dimension lines; figures readable from the bottom and right (1 each, max 3).
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