**Engineering Drawing -**

**Scales**

Similarly in case of tiny objects
dimensions must be increased for
above purpose. Hence this scale is called enlarging scale.

Here the ratio called representative
factor is more than unity.

Representative factor (r.f.) = Dimension of drawing / Dimension of object

Length of scale = r.f. * max. Length to be measured.

__Types of scales:__- Plain scales ( for dimensions up to single decimal)
- Diagonal scales ( for dimensions up to two decimals)
- Vernier scales ( for dimensions up to two decimals)
- Comparative scales ( for comparing two different units)
- Scale of cords ( for measuring/constructing angles)

__Plain scale__**Plain scale: -**This type of scale represents two units or a unit and its sub-division.

**Problem:-**Draw a scale 1 cm = 1m to read decimeters, to measure maximum distance of 6 m. Show on it a distance of 4 m and 6 dm.

**Construction:-**

Calculate r.f. = Dimension of drawing / Dimension of object

r.f. = 1cm/ 1m = 1/100

length of scale = r.f. x max. Distance

= 1/100 x 600 cm

= 6 cms

B) Draw a line 6 cm long and divide it in 6 equal parts. Each part
will represent larger division unit.

C) Sub divides the first part which will represent second unit or
fraction of first unit.

D) Place (0) at the end of first unit. Number the units on right
side of zero and subdivisions. On left-hand side of zero. Take height of scale
5 to 10 mm for getting a look of scale.

E) After construction of scale mention its rf and name of scale as
shown.

f) Show the distance 4 m 6
dm on it as shown.

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Article By

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**N.Nagendra Kumar**

Assistant Professor

Mechanical Department

LAQSHYA Institute of Technology & Sciences

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