import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,17))
r=w0.workplane(offset=-43/2).moveTo(-30,-28).cylinder(43,20).union(w0.sketch().segment((21,17),(24,17)).segment((24,5)).segment((47,5)).segment((47,17)).segment((50,17)).segment((50,35)).segment((47,35)).segment((47,48)).segment((24,48)).segment((24,35)).segment((21,35)).close().assemble().push([(36,26)]).circle(2,mode='s').finalize().extrude(8))