Choosing Hammer Face and Stake
锤面与砧具的选型
标签：锤面曲率, 砧具形状, 匹配原则, 抛光锤, 蛋形砧
锤面曲率应略小于工件曲面曲率，才能把力集中到高点；过平则压不到凹谷，过凸则只点接触留下麻点。曲面器物配蛋形、楔形或马鞍形砧；深腔用长颈砧从内支撑。镜面工件用抛光钢锤面，避免二次划伤。每次作业前用细砂纸修掉锤面锈点。
The hammer-face curvature should be slightly smaller than the workpiece curvature so force concentrates on high spots; too flat misses valleys, too convex leaves pitting. Use egg-, wedge- or saddle-shaped stakes for curved forms; support deep cavities from inside with a neck stake. For mirror finishes use a polished steel face to avoid re-scratching. De-rust the face with fine paper before each session. ---