Explanatory notes
… simple mechanisms such as gearing, crank‑handles, plungers, screw mechanisms or levers. Appliances are, however, … Moreover, very few abrasive tools remain in the scope of the Chapter (see the Explanatory Notes to headings … subject of a special heading. Chains, nails, bolts, nuts, screws, rivets, springs (e.g. for secateurs) and other parts …