I have an old Square D Kollsman 3 pointer altimeter that I think it's
about 50 or more years old and seems to be in working condition. The
body is about 2 13/16 diameter. The label on the back says part no.
371K-05

The three altitude pointers give the usual altitude readout. The little
Kollsman barometer window works and I know how to synchronize a known
altitude with the known barometer pressure by removing the little screw
and pulling the Kollsman knob out for the 'calibration'.

Now here's my question. There are two extra little visible pointers on
this altimeter that both rotate around concentric circles centered on
the instrument face. What are these pointers for. One is on the outer
circumference of the dial and the other one is on a smaller inner
circle with a radius of about 1 inch. Both pointers rotate when the
Kollsman knob is turned. They do NOT respond to air pressure changes.
The outer one moves at the same rate as the hundreds altimeter pointer
when the knob is turned. The inner pointer increments 100 feet when the
outer pointer makes one complete revolution around the face.

What are these "extra" pointers for???? They seem to serve no other
purpose than measuring the rotation of the Kollsman knob.

Dennis