When specifying the depth of a cut, should the dimension start from the datum surface or from the surface where the cut will be made? In the example below, a cut of 5mm is made from the surface opposing datum surface A. Is the appropriate dimension 5 or 10?
I'm told to do it from the datum surface but wouldn't it be more convenient for the machinist if it were from the surface from which the cut will be made? The former requires additional maths whereas the latter is more obvious in terms of "what has to be done on the part"
Ok, the maths is not hard, but imagine having to do it 10 times and scribbling all over the drawing.