Scales are calipers without the internal/external measuring but they don't do them in decent lengths at affordable prices.
Have used Aldi verniers £5 to repair X and Y scales electronics, just a straight swap when they pack up.
Bought a load of verniers some years back from Chester when they used to have sales prices £1 boxed, some were over 3ft long in wooden box(well over £120 each). 2 out of 3 worked. Used to use them before I had a proper dros on the mills.