What is meant by positive and negative zero error in a screw gauge?
What is meant by positive and negative zero error in a screw gauge?
Positive zero error: Positive zero-error of 2 circular scale divisions. Positive zero-error correction is done by subtracting the positive zero-error from the actual reading.
Error: When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the zero of the head scale lies below the pitch scale axis, the zero error is positive.
Negative zero error: Negative zero-error of 4 circular scale divisions. Negative zero-error correction is done by adding the negative zero-error from the actual reading.
When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the Zero of the head scale lies above the pitch scale axis,the zero error is negative.
Positive zero error: Positive zero-error of 2 circular scale divisions. Positive zero-error correction is done by subtracting the positive zero-error from the actual reading.
Error: When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the zero of the head scale lies below the pitch scale axis, the zero error is positive.
Negative zero error: Negative zero-error of 4 circular scale divisions. Negative zero-error correction is done by adding the negative zero-error from the actual reading.
When the plane surface of the screw and the opposite plane stud on the frame are brought into contact, if the Zero of the head scale lies above the pitch scale axis,the zero error is negative.
