Several subheadings for non-numerically controlled grinding machines specify that the machine must be capable of positioning the working surface to an accuracy of at least 0.01 mm. Machines that do not meet this precision threshold are classified under the residual deburring and polishing subheading (846090) rather than the specific grinding subheadings. Manufacturers' technical specifications documenting positioning accuracy are the key supporting document.

A machine that both hones and grinds should be classified according to its principal function under the General Rules of Interpretation. If honing is the primary operation, 846040 applies; if grinding predominates, the relevant grinding subheading applies. For machines where the functions are genuinely equal, GRI 3(c) directs classification to the subheading that occurs last in numerical order, but a binding ruling is advisable for high-value equipment.