Photographer's Note

Im not going to explain in details what this all about and how it works. I am not a mechanical engineer (only an electrical ;-) and the text might be to long.

In order to find the best design for an adjustable spanner (for instance) its necessary to know about the tensions inside the matter (steel). A computer can do this kind of calculations in a few minutes (or seconds) once the data entered to the program.
For 50 years ago the calculation had to be done by hand and hence alternative methods was developed to make tensions visible by experiments.

First an enlarged model of the item is made in a special plastic material. When placed between two polarisation filters (the same kind as for cameras and sunglasses) noting special happens so far. But when the model is exposed with a force, the tension in the plastic material will course deformation, which again course interference of the light, seen as colour changes.
Many colour changes means bigger tension and a place where the spanner might break Note that the tension in the spanner and the nut are corresponded.

The mirror impression of my watch gives an idea of the sizes.

Second note: To give a better view of the equipment have I uploaded this

Catcher, mitternacht, jurgen, alvaraalto has marked this note useful

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Additional Photos by Jeppe Madsen (Jeppe) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 3938 W: 385 N: 4195] (18654)
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