import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,-10))
r=w0.sketch().push([(-75.5,29)]).rect(49,8).push([(-76,29)]).circle(3,mode='s').finalize().extrude(-56).union(w0.workplane(offset=76/2).moveTo(55.5,0).box(89,128,76))