长度较短的直尺，用于非常精确的工作，有一个工作边缘是斜切的，非常轻微地磨圆（“刀口”）。材料、一般特征、饰面、精度、把手、玻璃试板、外壳、包装、标记。交叉引用:BS 817BS 818BS 863BS 869BS 870BS 887BS 888BS 906BS 907BS 939BS 957BS 958BS 959BS 1054BS 1643

Straightedges of short length for very accurate work, having one working edge which is bevelled and very slightly rounded off ('knife-edge'). Material, general features, finish, accuracy, handles, glass test plate, case, packing, marking.Cross References:BS 817BS 818BS 863BS 869BS 870BS 887BS 888BS 906BS 907BS 939BS 957BS 958BS 959BS 1054BS 1643