Base plate pole design

The base plate has four poles to extend to the next layer. The poles are 3.5 cm in length with a radius of 0.7 cm. We can extend to the next plate by attaching hollow tubes to the poles. At the top of the hollow tube, we will insert a hard plastic to make a screw hole. This hole will be useful for extending to the top layer. The base plate pole and hollow tubes on each pole are shown in the following diagram. The hollow tube has a radius of 0.75 cm and length of 15 cm:

Design of hollow tube 15 cm