Plain scale Engineering Graphics

Plain scale
Engineering Graphics
Engineering Drawing

1. ENGINEERING GRAPHICS PLAIN SCALE

2. Reduced scale: Dimensions of large objects must be reduced to draw on standard size drawing sheet. Example: Map Of any country

3. Enlarged scale: Similarly in case of tiny small objects dimensions must be increased to draw on drawing sheet. Example: Drawing of wrist watch parts.

4. TYPES OF SCALES PLAIN SCALES DIAGONAL SCALES

5. What is plain scale? A plain scale consists of a line divided into suitable number of equal units. The first unit is subdivided into smaller parts. The plain scales give only two dimensions, such as a unit and it's subunit or it's fraction.

6. LENGTH OF SCALE = ( R.F. ) × (MAX. LENGTH TO BE MEASURED.) Two Formulas For The Calculations

7. PROBLEM NO.1 Draw a scale 1 cm = 1 meter to read meters and decimeters, to measure maximum distance of 6 m. Show on it a distance of 4 m and 6 dm.

8. SOLUTION:-

9. R.F.= 1cm/ 1meter = 1/100 We know that, 1 meter = 10 decimeter = 100 cm Length of scale = (R.F.) X max. distance = 1/100 X 600 cm = 6 cms

10. ……ANSWER Take height of scale 5 mm to 10 mm for getting a look of scale

11. PROBLEM NO.2 In a map a 36 km distance is shown by a line 45 cms long. Calculate the R.F. and Construct a plain scale to read kilometers and hectometers,for measuring maximum 12 km distance. Show a distance of 8.3 km on it.

12. CONSTRUCTION :- Calculate R.F . R.F .= 45 cm/ 36 km = 45 cm/ (36 × 1000 × 100)cm = 1/ 80,000

13. Length of scale = (R.F.) × max. distance = (1/ 80000) × 12 km = (1/ 80000) × (12 × 1000 × 100)cm = 15 cm

14. Take height of scale 5 mm to 10 mm for getting a look of scale ……ANSWER

15. Problem 3: Construct a plain scale to show kilometers and hectometers when 25 mm is equal to 1 km and long enough to measure up to 6 km. Find RF and show a distance of 3km and 4 hectometer on the scale.

16. Problem 4: Construct a plain scale of R.F. = 1:50 to show meters and decimeters and long enough up to 8 meter. Indicate 6.7 m distance on scale

17. Problem 5: Construct a plain scale with RF = 1/5 to show decimeters (dm) and centimeters. The scale should be long enough to measure 1 m. Show the length of 7.4 dm on it.