import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,13))
r=w0.sketch().segment((-50,-21),(-19,-21)).arc((0,-29),(19,-21)).segment((50,-21)).segment((50,21)).segment((19,21)).arc((0,29),(-19,21)).segment((-50,21)).close().assemble().finalize().extrude(-26)