Least count of a screw gauge
The pitch is 1 mm and the circular scale has 100 divisions, so the least count is 0.01 mm.
Least count
0.01mm
= 0.001 cm
1 mm / 100 = 0.01 mm
Least count = pitch / number of circular scale divisions.
Least count = pitch / number of circular scale divisions
A screw gauge is used for the thickness of wires and sheets up to about 25 mm. The working for the textbook numbers is 1 mm / 100 = 0.01 mm.
Other instruments
Screw gauge: quick answers
What is the least count of a screw gauge?
The pitch is 1 mm and the circular scale has 100 divisions, so the least count is 0.01 mm. Least count = pitch / number of circular scale divisions.
How do I find the least count of my screw gauge?
Least count = pitch / number of circular scale divisions. For the instrument in front of you, read the scale and use your own numbers in the tool above.
Why does the least count matter?
The least count is the smallest reading you can make, so it sets the smallest error in a single measurement. Screw gauge measures the thickness of wires and sheets up to about 25 mm.
What is the pitch of a screw gauge?
The distance the screw moves along its axis in one full turn of the circular scale, read on the main scale.