This set of Engineering Drawing Multiple Choice Questions & Answers (MCQs) focuses on “Terminology of Dimensioning – 1”.
a) A leader line is a thin continuous line connecting a note or a dimension figure.
b) One end of the leader terminates either in an arrowhead or a dot.
c) The leader is drawn vertical or horizontal or curved.
d) Use of common leaders for more than one feature should never be made.
Explanation: The leader is never drawn vertical or horizontal or curved. It is drawn at a convenient angle of not less than 30o to the line to which it touches. When pointing to a circle or an arc it is drawn radially.
Explanation: Centre line usually represents the centre of circle, the axis of cylindrical objects, lines of symmetry, trajectories, pitch circle of gears and pitch circle of holes, represented by chain thin long-dashed dotted (narrow).
Explanation: An extension line also a thin continuous line drawn in extension of an outline. It extends by about 3 mm beyond the dimension line. Dimension line is a thin continuous line. It is terminated by arrowheads touching the outlines, extension lines or centre lines.
4. While representing the diameter in dimensioning it is represented as __________
Explanation: Diameter is represented the unique way as shown in options which directly represents the circle and line at its center that is center line where diameter is measured. But radius is represented as capital R.
a) a, i; b, ii; d, iii; e, iv
b) a, iv; b, iii; d, ii; e, i
c) a, i; b, iv; d, iii; e, ii
d) a, iii; b, ii; d, i; e, iv
Explanation: Chain thin long-dashed dotted (narrow) is used for centre line. Dashed thin (narrow) is used for hidden outlines and hidden edges. Continuous thin (narrow) (straight or curved) is used for extension line as well as dimension line, but dimension line has arrow heads at ends.
Explanation: A note gives information regarding specific operation relating to a feature. It is placed outside a view but adjacent to the feature concerned. It is so written that it may be read when the drawing is viewed from the bottom edge.
7. It is recommended that a gap of about 2 mm should be kept between the extension line and an outline.
Explanation: It is recommended that a gap of about 1 mm should be kept between the extension line and an outline or object boundary by the B.I.S. It extends by about 3 mm beyond the dimension line.
Explanation: Arrowheads should ordinarily be drawn within the dimensioned feature. But when there is fewer space arrowheads can also be kept outside and a dot may also be used to replace arrowhead and also if there is no space for dimension figure to be kept on dimension line the figure may be written above the extended portion of dimension line.
Sanfoundry Global Education & Learning Series – Engineering Drawing.
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