Posted by Robert Atkinson 2 on 01/03/2019 13:01:27:
Most likely for a measurement indication point that was relatively distant from the adjustment / setting location position. Now we would just use a electronic sensor with a remote display.
Exactly that, I spent some time working in an engineering laboratory testing various structures. These structures would be festooned in these large DTI's, easy to read. Could get a bit tedious with 30 – 40 of them to read and record. We were delighted when electronics made them, for us, largely obsolete. I remember boxes of them going in to a skip when electronics became cheap and easy!