To unde underst rstan and d work workin ing g prin princi cipl plee and and meas measur urem emen entt usin using g Slip Slip Gaug Gauges. es. To calibrate the given Micrometer using Slip Gauge and to plot the calibration graph. INSTRUMENTS REQUIRED: 1. Micrometer Range : 25-50mm 25-50mm L.C. : 0.01mm 2. Slip Gauges Gauge block set of grade A (87pcs) WORKING FORMULAE: For drawing the best line and obtaining the calibration equation, y = mx + c
m
c
=
=
∑ x∑ y − n∑ xy ( ∑ x ) − n∑ x 2
2
∑ y − m∑ x n
Where, x y m c n
= = = = =
Slip Gauge reading Micrometer reading Slope of best fit line y-intercept of best fit line. number of measurements
PRECUATIONS: Gauge blocks are handled carefully so as not to damage the surfaces. It should never be keep as measuring face to bottom. PROCEDURE: 1. Note Note down down least least count count and zero zero error error of Micro Micromet meter er 2. The gauge gauge blocks blocks are cleaned and all grease grease is removed removed.. 3. Gauge blocks blocks are wringed wringed to make make the required required dimensio dimension. n. 4. The dimensi dimension on of gauge gauge blocks blocks is measured measured using using micromet micrometer. er. 5. The result result is tabulated tabulated and the the process process is repeated repeated to get a set set of reading reading 6. The calibratio calibration n graph is is plotted plotted and calibrati calibration on equation equation is found found out. out.
OBSERVATIONS AND CALCULATIONS: 1. Micrometer Range = Least count = Zero error =
CALIBRATION OF MICROMETER AND VERNIER CALIPER
-1-
VJCET
Sl No.
MECHANICAL MEASUREMENTS LABORATORY Slip Gauge reading in mm (x)
Micrometer reading in mm (y)
∑ x =
∑ y
x2
xy
1 2 3 4 5 6 n
=
Slope of best fit line,
m
=
Y-intercept of best fit line,
∑ x
=
∑ x ∑ y − n∑ xy ( ∑ x ) − n∑ x 2
c
=
2
∑ y − m∑ x
2
∑ xy
=
=
=
n
Equation of best fit line y = mx+c = SAMPLE GRAPH:
90 80 70
R 60 r e t e 50 m o r c 40 i M 30 20 10 0 10
25
40
55
70
85
Slip Gauge Reading
Fig.1 – Calibration Graph
RESULT: The given Micrometer is calibrated using slip gauges and the calibration graph is plotted. The calibration equations are: 1. For Micrometer, y= INFERENCE:
