import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,-25))
w1=cq.Workplane('XY',origin=(0,0,-50))
r=w0.sketch().push([(0,2.5)]).rect(8,69).push([(1,-19)]).circle(3,mode='s').finalize().extrude(75).union(w1.workplane(offset=20/2).moveTo(0,-29.5).box(40,15,20))