SHORT QUESTION ANSWERS-DRAWING SCALES
SHORT QUESTION ANSWERS
Reduced and enlarged scales are used
for large and small objects. Full scale is
used for objects whose dimensions are
manageable on the drawing sheet.
Q1– What is a scale?
A scale by which we keep same or reduce or increase the actual size of the object on a drawing.
Scale = Size taken on the drawing / Actual size
Q2 What are various types of scales used in drawing?
There are three types of scales used in drawings.
1) Full size scale
The scale in which the actual measurements of the object are drawn on the drawing is full size scale. For example 1:1
2) Reducing scale
The scale in which the actual measurements of the object are reduced to some proportion is known as reducing scale. For example 1:4
3) Enlarging scale
The scale in which the actual measurements of the object are increased to some proportion is known as enlarging scale. For example 2:1
Q3 – What is the representative fraction (R.F.) or scale factor (S.F.)?
The ratio of the drawing size of an object to its actual size is called the Representative fraction.
R.F. = Dimension of an object on the drawing sheet / Actual dimension of an object
For example 1/10. It is always written a/b.
Q4 – What are the main uses of scale?
Ans – The following are the main uses of scale in engineering practice.
(i) The scales are used to prepare reduced or enlarged size drawings.
(ii) The scales are used to set off dimensions.
(iii) The scales are used to measure distances directly.
Q5 – What are the information necessary for scale?
Ans – To construct a scale, the following information are necessary.
(i) The representative fraction (R.F.) of the scale.
(ii) The units to be presented (SI UNITS)
(ii) The maximum length of the scale
Q6 – What is difference between a plain scale and a diagonal scale?
A plain scale is simply a line which is divided into a suitable number of equal parts. The first part of which is further sub-divided into small parts. It is used to represent a unit and its fraction such as meters and decimeters (m and dm). It contains only two units (ones and tens or tens and hundred)
A diagonal scale is used when measurements are required in three units; for example dm, cm, and mm (ones, tens and hundreds).
Q7 – What is the principle of a diagonal scale?
Ans7: – The principle of diagonal scale is to divide a short line into ten equal parts. It is followed by the diagonal division into another ten parts.