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It consists of a U-shaped frame fitted with a screwed spindle which is attached to a thimble.


Screw-gauge

The screw has a known pitch such as 0.5 mm. Pitch of the screw is the distance moved by the spindle per revolution. Hence in this case, for one revolution of the screw the spindle moves forward or backward 0.5 mm. This movement of the spindle is shown on an engraved linear millimeter scale on the sleeve. On the thimble there is a circular scale which is divided into 50 or 100 equal parts.
When the anvil and spindle end are brought in contact, the edge of the circular scale should be at the zero of the sleeve (linear scale) and the zero of the circular scale should be opposite to the datum line of the sleeve. If the zero is not coinciding with the datum line, there will be a positive or negative zero error as shown in figure below.


Zero error in case of screw gauge While taking a reading, the thimble is turned until the wire is held firmly between the anvil and the spindle.

The least count of the micrometer screw can be calculated using the formula given below:
Least count

= 0.01 mm

Determination of Diameter of a Wire
The wire whose thickness is to be determined is placed between the anvil and spindle end, the thimble is rotated till the wire is firmly held between the anvil and the 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 figure below.


Reading = Linear scale reading + (Coinciding circular scale x Least count)

= 2.5 mm + (46 x 0.01)
= (2.5 + 0.46) mm

= 2.96 mm
Relationship in the Metric system of length

1 kilometer (km) = 103 m
1 centimeter (cm) = 10-2 m
1 millimeter (mm) = 10-3 m

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It consists of a U-shaped frame fitted with a screwed spindle which is attached to a thimble.


Screw-gauge

The screw has a known pitch such as 0.5 mm. Pitch of the screw is the distance moved by the spindle per revolution. Hence in this case, for one revolution of the screw the spindle moves forward or backward 0.5 mm. This movement of the spindle is shown on an engraved linear millimeter scale on the sleeve. On the thimble there is a circular scale which is divided into 50 or 100 equal parts.
When the anvil and spindle end are brought in contact, the edge of the circular scale should be at the zero of the sleeve (linear scale) and the zero of the circular scale should be opposite to the datum line of the sleeve. If the zero is not coinciding with the datum line, there will be a positive or negative zero error as shown in figure below.


Zero error in case of screw gauge While taking a reading, the thimble is turned until the wire is held firmly between the anvil and the spindle.

The least count of the micrometer screw can be calculated using the formula given below:
Least count

= 0.01 mm

Determination of Diameter of a Wire
The wire whose thickness is to be determined is placed between the anvil and spindle end, the thimble is rotated till the wire is firmly held between the anvil and the 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 figure below.


Reading = Linear scale reading + (Coinciding circular scale x Least count)

= 2.5 mm + (46 x 0.01)
= (2.5 + 0.46) mm

= 2.96 mm
Relationship in the Metric system of length

1 kilometer (km) = 103 m
1 centimeter (cm) = 10-2 m
1 millimeter (mm) = 10-3 m

]]> http://www.lankaedu.com/thread-6.html Fri, 05 Feb 2010 04:28:57 +0300 http://www.lankaedu.com/thread-6.html ]]> ]]> http://www.lankaedu.com/thread-5.html Fri, 05 Feb 2010 03:58:45 +0300 http://www.lankaedu.com/thread-5.html [Grade 10] බුද්ධ ධර්මය - විෂය නිර්දේශය
]]> [Grade 10] බුද්ධ ධර්මය - විෂය නිර්දේශය
]]> http://www.lankaedu.com/thread-4.html Fri, 05 Feb 2010 03:42:55 +0300 http://www.lankaedu.com/thread-4.html ]]> ]]> http://www.lankaedu.com/thread-3.html Fri, 05 Feb 2010 03:40:00 +0300 http://www.lankaedu.com/thread-3.html ]]> ]]> http://www.lankaedu.com/thread-2.html Thu, 04 Feb 2010 10:43:19 +0300 http://www.lankaedu.com/thread-2.html
We are happy to welcome you all to our newest site, 'LankaEdu.com' - A community fully dedicated to improve sri lankan education!

This website is going to be a whole new experience for you.
you can post your education materials you have with you to share them with others & be helpful.

- LankaEdu Staff
Navathena Network. ]]>
We are happy to welcome you all to our newest site, 'LankaEdu.com' - A community fully dedicated to improve sri lankan education!

This website is going to be a whole new experience for you.
you can post your education materials you have with you to share them with others & be helpful.

- LankaEdu Staff
Navathena Network. ]]> http://www.lankaedu.com/thread-1.html Thu, 04 Feb 2010 10:30:15 +0300 http://www.lankaedu.com/thread-1.html
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