And create 2 rectangle like a plus sign and attach them on editable spline, then in connect copy select Boolean and with this part remove between line in 2 rectangle (show in the picture).
Ok, for your cylinder > Go to shape merge and select + . Then go to editable poly and extrude new polygon about (-0.03cm).
Step 13:Create a chamfer box with theses parameters Length=28.0cm, Width=4.0cm, Height=1.0cm, Fillet=0.25cm. Then convert into editable poly and with slice plane remove the bottom side of the chamfer box.
Step 14:Create a box model with these parameters.
Select the polygon mode in the Editable poly and move the vertexes as shown in the following series of image.