Dave Plowman (News) wrote:

It's often impossible to read a spirit level accurately because you can't
get an eye square on to it.

Use a small mirror to read it.

So are those digital readout ones any good -

As most of you are aware, I used to work in the aerospace industry and
one of the jobs I used to do was check the taileron angles (taileron is
a half of a tail plain that can be at any angle, independent of the
other half. Unlike a tail plane that has to be at the same angle as the
other side and creates the roll by using ailerons on the wings.)

In the old days, we used to use pantographs to measure the angles, which
were quite accurate. Then we moved on to digital angular measures. They
became the biggest pain in the arse. 0.1 degree could be the difference
between pass and fail for the test.

Make your own mind up about them, if you want that much accuracy.

Never having seen one, another thought is, how do you calibrate one?

Dave