for grinding cylindrical surfaces both externally and internally with several grinding wheels

Full Title

Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor (B24B11/00 - B24B21/00 take precedence; honing machines or devices using abrading blocks performing axial and rotary movements superimposed on one another B24B33/00) > involving centres or chucks for holding work > for grinding cylindrical surfaces both externally and internally with several grinding wheels