import cadquery as cq
w0=cq.Workplane('YZ',origin=(30,0,0))
r=w0.workplane(offset=-61/2).moveTo(-78,-15).cylinder(61,22).union(w0.sketch().push([(58.5,0)]).rect(83,78).push([(78,-10)]).circle(15,mode='s').finalize().extrude(-46))