Screw Gauge

In solutions they have taken zero error to be +3* L.C. but as zero is below the line zero error must be 3* L.C. RIGHT?

@pankaj497 it's correct we need to take +3 we take  when zero is above mean line

@pankaj497 Understand with example you have a 10 kg bag of rice but your weighing scale zero is above mean line at 3 kg then your reading would come 7 kg

@pranaysinha So when fully tightened the mean line will coincide with what reading on the circular scale 3 or 97?

@pranaysinha How to understand this Zero Error concept easily plzz explain SIR

@pankaj497 think as if since the reading will always be three less than what actual reading should be so solve normally then add 3 in the circular scale reading

@pankaj497 On 3 read carefully the zero lies below mean line and not vice versa as in given case