The usual way to measure such small distances is using
an optical microscope that has an eyepiece with micrometer
controlled moving reference lines. Zero the micrometer
with the reference lines at some known distance... usually
overlapping, and then adjust them to match the head gap.
The micrometer reading gets multiplied by the optics to
arrive at the actual gap.
Absent one of those special oculars, you can use a finely
ruled ruler, placed in the same frame as the gap, and
extrapolate the size of one of the lines to the gap.
If you have some fine wire, that you can measure with a
micrometer, you can compare it to the gap...
When the sizes get even smaller, a scanning electron microscope
can easily perform the same duty.
-Chuck Harris
snapdiode via Groups.Io wrote:
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Dear massed wisdom of this group, how would you measure the head gap of a floppy disk r/w head?
By counting pixels on a microscope pic I've arrived at the more or less believable 0.35 mils, or 0.009mm . One thing's for sure, it's tiny.
But that number is ten times smaller than the one reference I found that says it is 80 microns, or 0.08mm.
