Measuring Connector Pitch
We use our calipers to verify component sizes, sometimes these numbers are in the datasheet but once in a while we have a part for which the datasheet is incomplete or we just want to verify. If you're measuring a dense connector, its a good idea to measure over a large number of pins and then average.For example, on this 37-pin FPC (flex circuit board) I'm measuring between the center points (as far as I can manage) of the two outer pins.
Remember that for a N pin connector, there are N-1 'gaps' (a common-enough confusion that it has its own name, the fencepost-error ) so divide 35.68mm by 36 = 0.99mm. Since we're eyeballing the center points of the connector, this should be rounded up to a 1mm pitch. Sometimes the number should be rounded up/down in imperial so if it seems off, check other units.
Measuring Pin-to-Pin Distance
A nice trick you can do with digital calipers is zero'ing out the origin. For example, lets say we have a connector with pins, we want to measure the pin distance. First measure the pin thickness.
Zero it out.
Now you can measure on the outer edges of the pins and it will automatically subtract one pin thickness.
In this case there are 4 pins, so divide 11.92mm by 3 to get 3.97mm, which we'll round up to 4mm since we know its a metric part.
