If R.F is 1.5000 prepare a simple comparative and diagonal seal
Answers
The maximum length of the scale to be constructed on the drawing sheet =
R.F X maximum length the scale should measure.
This should be generally of 15 to 20 cms length.
Table: Metric Units Table: FPS Units
1 Kilometre (km) =10 Hecta metres (hm) 1 Mile =8 Furlongs
1 Hectametere(hm) =10 Decametres(dam)or 0.1km 1 Furlong =220 Yards
1 Decametre(dam) =10 Metres (m) or 0.1hm 1Yard =3 Feet
1 Metre(m) =10Decimetres(dm) or 0.1dam 1 Feet =12 Inches
1 Decimetre(dm) =10 Centimetres(cm) or 0.1m
1 Centimetre(cm) =10 Millimetres (mm) or 0.1dm
The various types of scales used in practice are 1. Plain or Simple scales, 2. Diagonal scales, 3. Vernier scales, 4. Comparative scales and 5. Scale of chords.
Simple or Plain Scales: They read or measure upto two units or a unit and its sub-division, for example centimetres (cm) and millimetres (mm). When measurements are required upto first decimal, for example 2.3 m or 4.6 cm etc. It consists of a line divided into number of equal main parts and the first main part is sub-divided into smaller parts. Mark zero (O) at the end of the first main part. From zero mark numbers to the main parts or units towards right and give numbers to the sub-divisions or smaller parts towards left. Give the names of the units and sub-units below clearly. Indicate below the name of the scale and its R.F clearly.
The construction of the plain scale is explained below by a worked example.
A 3 cm long line represents a length of 4.5 metres. Extend this line to measure upto 30 metres and show on it units of metre and 5 metre. Show the length of 22 metres on this line.