… coach screws, screw hooks, rivets, cotters, cotter-pins, washers (including spring washers) and similar articles, of iron or steel. …
Explanatory notes
… coach screws, screw hooks, rivets, cotters, cotter‑pins, washers (including spring washers) and similar articles, of … a steeper cutting thread since they have to bite their own way into the material. Further, wood screws almost always … bore, to prevent the relative movement of parts. (E) WASHERS Washers are usually small, thin discs with a hole in …