It is obvious that the radial face of the work at the cone plate end, as well as the circumference, must be trued up, so that the work end may have equal contact around the bore of the coned rings.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose
When the work is centred, it should, for reasons already explained, have its end faces trued up.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose
Straight-edges are sometimes made of cast steel and trued on both edges.
"Modern Machine-Shop Practice, Volumes I and II"
Joshua Rose