| 摘要 |
<p>The set square is magnetic and flexible to adhere to curved surfaces. It is used for marking out and similar purposes in sheet metal work, plating and automobile bodywork. It comprises a thin sheet (1) of flexible metal, cut to the shape of a set square. On its underside is fixed a thin layer (2) of magnetic material. The centre portion is removed and one inner edge, folded up to form a bracket (3). A cam lever (5) is pivoted (4) to this, its profile projecting below the magnetic surface when the lever is pressed down (5); this enables the square to be positioned and removed.</p> |
