Today on Repairs101 I’m going to show you
how to read the three most common types of Vernier Scale calipers.
These are the callipers I’ve collected to represent the three Vernier scales.
Now a digital calliper is easier, more accurate and way more fun to use but a Vernier scale
doesn’t need batteries. A Vernier scale is a movable scale running
parallel to a fixed scale. They measure very accurately in metric, imperial decimal and
imperial fractions. Calipers measure three different ways: outside
measurements, inside measurements and depth measurements.
Now if you have a lot of nearly identical things to measure you might find that this
fine adjustment screw makes the job easier by anchoring at a point that’s within reach
of the target area – then all you need is the fine adjustments to find each individual
measurement. To read this in metric we look at the lower
fixed scale. The Vernier’s zero is just over one centimetre, so we go across the Vernier
scale to see where the lines match up exactly. This is an oil pump gear and to find the size
of the shaft that drives it you just take an inside measurement.
On this calliper, if you’re looking for an imperial decimal measurement you look at
the upper scales – ignoring the lower metric scales and you see that a US quarter measures
zero point nine five inches.