import cadquery as cq
w0=cq.Workplane('ZX',origin=(0,2,0))
r=w0.sketch().push([(0,-1)]).circle(12).circle(4,mode='s').finalize().extrude(-52).union(w0.sketch().arc((-15,-37),(6,-16),(36,-16)).arc((-15,34),(-15,-37)).assemble().finalize().extrude(48))