Measuring the depth in a hole…

[Okapi]

Thanks Schor,
The foot is totally independent then you can use any form you want, this one is fixed but another bar is made in minutes if needed(I have three others made for special applications).
As you need a the beginnig a calibration when it's not just a comparative use, the form is not important, all you want, it's just a basis for the measurment, not a fuctional piece.