MEASUREMENT AND MEASURING TOOL-FITTER ONLINE NOTE

1. MEASUREMENT INTRODUCTION

i)- Working in workshop or making job or manufacturing machine parts some sizes are given in the drawing like length, breadth, height, thickness, diameter, radius or angle, etc. 

ii)- To make same size and shape of jobs it is very essential that it should be correctly

measured. 

iii)- Since their production depends upon these sizes. 

iv)- Making of some special type of parts or job as per drawing in a workshop we have to measure and inspect so for that some instruments are required known as measuring tools.

2. MEASURING

i)- Size of some work piece measured in standard unit is known as measurement.

ii)- Manufacturing of machine parts in a workshop are always according to specific measurement.

iii)- its accuracy depends upon quality of measuring tools and skill of the worker. 

3. TYPES OF MEASURING

There are four system to measuring types of any job:

1. Linear Measurement:- 

i)- Measurement in straight line is known as linear measurement. 

ii)- These measurement can be taken by a)- steel rule, b)- vernier caliper and 

c)-micrometer etc.

2. Angular Measurement:- 

i)- Measurement of an angle created by two lines is called angular measurement. 

ii)- It is normally measured by a)- try square, b)- angle gauge, c)- vernier bevel protractor, d)- sine bar etc.

3- Radial Measurement:- 

i)- Circular measurement at round, spherical or semi-spherical job is called radial measurement. 

ii)- It is normally measured by a)- plug gauge, b)- ring gauge, c)- radius gauge etc.

4. Plain Surface Measurement:- 

i)- The measurement of surface accuracy is called plain surface measurement. 

ii)- To check the accuracy of such type of job, the following types of instruments are used like surface plate, surface gauge, straight edge, dial test indicator etc.

3. MEASURING METHOD

There are three system to measuring method of any job:

1. Direct Measurement: 

i)- In this system the job is directly measured by steel rule, micrometer, vernier caliper, bevel protractor etc.

Direct Measurement

2. Indirect Measurement: 

i)- In this system the job is measured by caliper, telescopic gauge, divider then final reading taken by measuring the above tools on steel rule.

ii)- some other tool is required for measuring the job like steel rule etc.

Indirect Measurement

3. Comparative Measurement: 

i)- In this system, measurement of job is known by compared(Template) with master piece.

4. MEASURING INSTRUMENT:-

i)- Making of jobs as per drawing in the workshop and to have its accuracy, the measuring instruments are required. 

ii)- These are divided into two groups 1)- Ordinary Measuring Tools and Instruments. 

2)- Precision Measuring Tools and Instruments

1. Ordinary Measuring Tools and Instruments:- 

The instruments which can measured minimum of 0.5 mm in Metric system and 1/64" in British system are known as ordinary measuring tools and instruments like steel rules.

2. Precision Measuring Tools and Instruments:-

i)- The instruments which can measure smallest and accurate quantity is called precision measuring instrument.

ii)-  these can measure up to 0.001" in British system and 0.01 mm in Metric system or measure more accuracy than it micrometer and vernier caliper etc.

5. SYSTEMS OF MEASUREMENT:-

These are mainly of three types: 1. C.G.S. or Metric system 2. F.P.S. or British system 3. M.K.S. system.

Note: Now-a-day's mostly C.G.S. and F.P.S. system are used.

1. C.G.S. or Metric System: 

i)- This system is normally used in our daily life. On the basis of IS! (Indian Standard Institute) and ISO (International Standardization Organization) most of the countries give their consent in its favor. 

ii)- In this, length is measured in cm, weight in gram, time in second and temperature in Celsius,

2. F.P.S or British System:- 

i)- This system was very much popular in our country. It is known as foot,pound and second system.

ii)- British standard system was invented in 1855 and commonly used but now B.S.I. has also adopted metric system.