Three kinds (flat type screw type universal type) of chains were made. Three kinds of chains were connected with the trial. An axis may not rotate immediately after 3D-Printing. In this case, probably, it will be good to impose power so that it may break lightly. Moreover, please twist a universal type lightly. However, when impossible power is imposed, it may break. There is a direction which inserts a pin. Please do not push in a pin by force. Moreover, please fasten loosely. The combination of connection is arbitrary. Probably, it will also be good to create two or more chains same type, and to connect them. Moreover, it may also be good to connect your favorite thing with a chain.