Free Sinking Basics
自由下凹（Sinking）基本步骤
标签：下凹, 凹砧, 锤击, 中心, 延展
将圆片置于凹砧孔上，使中心对准凹口，用圆头锤从中心向边缘画圈锤击，金属受挤压向下凹入并径向延展。每圈外移并旋转工件保证对称。下凹越深壁越薄，需勤退火。完成后边缘会起波浪，翻转在平砧上敲平。
Set the disc over a stake hole aligned to the centre, then strike in circles from centre to edge with a domed hammer so the metal is squeezed down and stretches radially. Move outward per ring and rotate for symmetry. Deeper sinking thins the wall, so anneal often. The rim will wave — flip and flatten it on a flat anvil. ---