Advertisements
Advertisements
Question
Describe the procedure to measure the diameter of a wire with the help of a screw gauge.
Advertisements
Solution 1
Measurement of diameter of wire with a screw gauge:
The wire whose thickness is to be determined is placed between the anvil and spindle end, the thimble is rotated until the wire is firmly held between the anvil and spindle. The rachet is provided to avoid excessive pressure on the wire. It prevents the spindle from further movement. The thickness of the wire could be determined from the reading as shown in the figure below.
The pitch of the screw = 1 mm
L.C. of screw gauge = 0.01 mm
Main scale reading = 2.5 mm
46th division of circular scale coincides with the base line.
Therefore, circular scale reading = 46 × 0.01 = 0.46 mm
Total reading = Main scale reading + circular scale reading
= (2.5 + 0.46) mm
= 2.96 mm
Solution 2
The following procedure is used to measure the diameter of a wire
(a). Calculate the least count and zero error of the screw gauge.
(b). Place the wire in between the studs. Turn the ratchet clockwise so as to hold the wire gently in between the studs. Record the main scale reading.
(c). Now record the division of circular scale that coincides with the baseline of the main scale. This circular scale division multiplied by the least count will give circular scale reading.
(d). The observed diameter is obtained by adding the circular scale reading to the main scale reading. Subtract the zero error if any, with its proper sign, from the observed diameter to get the true diameter.
APPEARS IN
RELATED QUESTIONS
When is a vernier Callipers said to be free from zero error?
(a) A vernier scale has 10 divisions. It slides over the main scale, whose pitch is 1.0 mm. If the number of divisions on the left hand of zero of the vernier scale on the main scale is 56 and the 8th vernier scale division coincides with the main scale, calculate the length in centimetres.
(b) If the above instrument has a negative error of 0.07 cm, calculate the corrected length.
(a) A vernier scale has 20 divisions. It slides over the main scale, whose pitch is 0.5 mm. If the number of divisions on the left hand of the zero of vernier on the main scale is 38 and the 18th vernier scale division coincides with the main scale, calculate the diameter of the sphere, held in the jaws of vernier callipers.
(b) If the vernier has a negative error of 0.04 cm, calculate the corrected radius of the sphere.
Define the term pitch.
Define the term least count as applied to a vernier callipers.
Which part of vernier callipers is used to measure the external diameter of a cylinder?
State the formula for calculating the least count of screw.
How do you account for negative zero error, for calculating the correct diameter of wires?
