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