Creating a pipe from boolean cut on cylinders.

Hi all,

I am trying to create a pipe by performing subtraction between two cylinders but getting a wrong shape. Instead of a pipe, the resulting shape is just the outer cylinder. Here is the dimensions:

TopoDS_Shape cylinder1 = BRepPrimAPI_MakeCylinder(gp_Pnt(0.0, 0.0, 0.0),
gp_Dir(1.0, 0.0, 0.0), 3e-6, 5e-5, 360).Shape();
TopoDS_Shape cylinder2 = BRepPrimAPI_MakeCylinder(gp_Pnt(0.0, 0.0, 0.0),
gp_Dir(1.0, 0.0, 0.0), 7e-6, 5e-5, 360).Shape();
BRepAlgoAPI_Cut cutOp(cylinder2,cylinder1);
TopoDS_Shape pipe = cutOp.Shape();

I thought that the problem might have been from overlapping faces so I tried making the inner cylinder longer but the result is still the same. Also, the intersection of these two cylinders is empty. Does anyone know what might have caused this and a possible solution?

Thanks.