Vernier Calipers PDF

mm (five VERNIER CALLIPERS 0.02 mm (two hundredths of a millimetre) or 0.05...

mm (five VERNIER CALLIPERS 0.02 mm (two hundredths of a millimetre) or 0.05 A metric Vernier calliper has an accuracy of either as identify the degree of accuracy of a Vernier calliper, hundredths of a millimetre). It is important that you calliper is Vernier callipers are a useful instrument for quick, reasonably accurate internal, external and depth the two. The degree of accuracy of a Vernier reading the measurement differs slightly between measurement. Like the micrometers, Vernier callipers may be calibrated in either metric or imperial Figure 93). engraved into the Vernier scale of the calliper (see the main measurement (or both). Vernier callipers can measure from zero millimetres up to the length of scale, commonly 150 mm, although they are available in much larger sizes. Figure 92 shows the main parts of a metric Vernier calliper. NOX TEMP ac Ni 120 130 140 150 Figure 92: Marking showing a Vernier calliper’s ‘degree of accuracy’ | ALTE TPG @ to means each division on the Vernier scale is equal Figure 93 shows a 0.02 mm Vernier calliper. This the total length of the Vernier scale equal to 1 mm. Alternatively, on a 0.05mm Vernier 0.02 mm, with to 0.05 mm. calliper; each division on the Vernier scale is equal Figure 91: Main parts of a metric vernier calliper Using a Vernier calliper There are measure outside, inside and depth dimensions. As mentioned earlier, the Vernier calliper can jaw is fixed, while the other (the jaw with the Vernier scale engraved on two ‘jaws’ on the calliper. One it) is movable. Main parts of an outside’ micrometer of a shaft (see Figure 94), the outside jaws Ss To measure outside dimensions, such as the diameter 1, Outside jaws 2. Vernier scale 3. Locking device the shaft and brought into contact with it. The locking device should then be are simply placed over ent is retained and can be read. engaged so that the measurem 4. Main scale 5. Inside jaws 6. Depth probe 60 Last updated March 2021 ; Northtec Lastupdated'March 2021 lb Northtec  rely on the surface of the calliper is placed squa in Figure 96. The end of g the moveable > Measuring depth is shown m of the orific e (hole) by slidin probe is moved to the botto device engaged. the opening. The depth moveable jaw) and the locki ng probe is attached to the jaw downward (the depth \ \t | — Moveable jaw Figure 93: Measuring an ‘outside’ dimension G Figure 95: Measuring depth an inside dimension, the inside jaws are inserted into the gap to be measured The > To measure i i surfaces and the locking i device engaged (see Reading a Vernier in Figure 97. Do not F oueeareaE,then brought into contact with jaws ith the internal in the followin g steps and Vernier calliper is explained must identify the The procedure to read a are fully close d. Firstl y, we reads zero when the jaws ate to 0.05 mm, as forget to check the Vernier shown in Fig ure 97 is accur Vernier scale. The example mm (five one degree of accuracy of the on the Verni er scale equal s 0.05 means that each division shown by the arrow. This four stages: ). The Vernier is read in hundredths of a millimetre 4. Whole millimetres (1.00 mm) mm) 2. Tenths of a millimetre (0.10 a milli metre (0.01 mm) 3. Hundredths of readi ngs are then added together. 4, The three Key Point hs of a millimetre. The actually measure oO ne hundredt Le | Remember that the Vernier cannot of five one hund redths of a millimetre shown in increments hundredths of a millimetre are. of a millimetre Figure 94: Measuring an ‘inside’ dimension (0.05), which is half of one tenth 61 Last updated March 2021 Northtec March 2021 Lastupdated  In Figure 96 we can see that the matching lines (as shown in the blue circle) are halfway between the ‘8’ and Whole millimetres (main scale) 9',: this means the tenths reading is 0.80. Because the matching line falls between the 8 and 9, 0.05 (five We first read the main scale, which is divided into whole millimetres (each division is equal to 4.00 mm). one hundredths of a millimetre) is also added. Now it is the simple process of adding the readings together: The reference point is the zero (0) on the Vernier scale; that is, we look at the ‘zero line’ (the red line in the green box in Figure 97) and note where it is positioned in relation to the main scale. Count the number of full millimetres on the main scale to the left of the zero. In Figure 97 (inside the green square) Vernier. calliper- reading’ (0:05 mm) we can see that this is 24.00 mm. Whole mm 24.00 a Tenths Hundredths 0.80 0.05 Total 24.85 mm ii tunniTiat HIT re a lol4 Reading a 0.02 mm vernier Reading a 0.02mm Vernier is very similar to reading a 0.05 mm Vernier. The difference is that the Vernier scale is further divided into five increments of 0.02 mm. Whole millimetres (Main scale) As with the 0.05 mm Vernier we first read the main scale by identifying where the ‘zero’ line of the Figure 96: Reading a 0.05 mm Vernier calliper Vernier scale is positioned against the main scale. In Figure 99 it is just past the 5 ‘line’, so the whole millimetres reading is 5.00 mm. Tenths and hundredths of a millimetre (Vernier scale) The second and third stages of the reading is 0 10 20 30 to read the Vernier scale. \ Main scale Each of the numbered divisions (1, 2, 3, etc.) is 0.10 mm (one tenth of a millimetre). The shorter vertical line between each of the numbers further divides the tenths of a alain millimetre into 0.05 mm increments (five one hundredths of a millimetre). What we are looking for is the first line on the Vernier scale ——_—_ Vernier scale that lines up precisely with a line on the main scale. Sometimes it appears that Seen 5 more than one of the lines on the Vernier scale foi Sip at eee NEE lines up with a line on the main scale. You can - ~ - 0.02mm 0.06mm make a more informed decision of which line should be used by identifying where the ‘zero’ ‘Zero' line is 0.04mm 0.08mm line is situated on the main scale. In Figure 98 nearly at 25 mm, L therefore the Figure 98: Reading a 0.02 mm Vernier calliper you can see that the zero line is closer to 25.00 Vernier reading mm than it is to 24.00 mm. This tells you that is going to be at the line you are looking for on the Vernier scale the ‘high’ end of will be at the higher numbered end of the scale. the scale Figure 97: Estimating where the ‘Vernier’ will be 64 Northtec Last updated March 2021 Wi Northtec Last'updated March 2021  Tenths and hundredths of a millimetre (Vernier scale) Next we read the Vernier scale. Each of the numbered divisions (1, 2, 3 etc) is equal to 0.10 mm (tenths Activity 5 Here are some definitions or meanings for words you have just learnt about. These are words you need to of a millimetre). The shorter vertical line between each of the numbers is equal to 0.02 mm (two one hundredths of a millimetre). know for your assessment. To read the tenths of a millimetre, find the first line on the Vernier scale that lines up precisely with a Read the meaning below and write the word you think best matches that meaning. line on the main scale. In Figure 99 this is shown by the blue lines. This line lies to the right of the ‘2’, but before the ‘3’ on the vernier scale, therefore the tenths of a millimetre reading is 0.20 mm. To read the hundredths of a millimetre, go back to the precisely matching Vernier and main scale lines (the blue lines). Figure 99 shows that each of the lines between the numbers on the Vernier scale aa “ e word represents 0.02 mm. There are three of the 0.02 mm divisions to the right of the ‘2’, so we add 0.06 mm to the calculation. Measurement system based on inches and feet This is what the calculation looks like: To check the accuracy of a scale or instrument Allowed variation in a measurement Measurement system based on the metre y Vernier, calliper reading (2:22 un) 6 Whole mm 5.00 ; The outside length of a circle Tenths 0.20 0.06 ; ,. Hundredths You might also want to check Check the feedback at the end of this assignment to see if you are right. Total 5.26 mm you spelt it right. 65 66 Northtec Last updated March 2021 v7, Northtec Last updated March 2021 li