A crane is a large, powerful device used to lift heavy objects. There are a large number of different types of cranes, each with a different use and application. Model makers like to re-create things from the real world, and a model crane is a complex project. Making one of these to scale, where it is the same proportions as a real crane, adds an extra element of challenge.
Research the type of crane you would like to build. There are a number of different styles, such as the hammerhead, the commercial and the gantry cranes (see Resources). You need pictures, measurements, and height and weight statistics.
Write a scale on the grid paper. For example, use the 1/2-inch squares on your paper to represent 10 real-life feet. Choose a scale which will allow you to draw and see details on the plan, but isn't too large to work with. If you need to, tape two or three sheets of paper together.
Sketch the crane design. Stick closely to your scale, so if the boom on the crane is 100 feet long, use 10 of the 1/2-inch spaces to draw the top and bottom of the piece. Draw the entire crane from multiple angles -- a side, top-down and front view at the least. Draw all of the struts inside the boom. Be precise, because you will use this scale diagram for your scale model.
Cut out pieces from your copper wire to the scale for your model. If you are using 1/2 inch to 10 feet, and the piece on the diagram takes up 100 feet, or 5 inches on your diagram, cut the piece to 5 inches long. Use the scale and the diagram to determine how long to cut all of the pieces, and cut out all of the pieces for your model.
Solder together the frame of each piece in flat sections. Heat up the copper wire with a soldering iron, then place the solder onto the wire, causing the end of it to melt and join the two pieces of copper. Lay out the left side of the main crane boom, and solder the pieces together. Repeat with the right-hand boom. Use the diagram to make the frame for your model.
Solder the struts into the frame of the model. Position the pieces so they mimic the pattern on your diagram, and solder the pieces together.
Cut pieces of the cabin out of sheet tin, using the tin snips. Solder the pieces together to form the device.
Assemble the crane pieces and solder it together. Leave the crane to cure overnight.
You can also build the crane out of balsa wood and glue, although you may benefit from using a wooden crane design instead of the metal design.