The sides are basically cut and weld frames (mitred corners or square butt as shown) with hinges and latches attached.
Because of the length of the sides, care needs to be taken that the framework does not twist or bow while building. Stagger the welding around the frame to help spread the weld heat.
Once the frames have been welded together, fit the antiluce latch plate 25mm down from the top of the top rail and flush with the outside face of the side.
NB - Remember to reverse the positions on the opposing side so you get two unique sides rather than two left or right sides!
Make up 8 sets of hinge straps and gudgeon pins for the sides as per the details below.
NB - Please note that the height of the hinge strap shown below is for a trailer with 17mm thick decking material - adjust the height to suit your proposed decking thickness.
Weld the first hinge strap flush with the front end upright (the latch plate end). At the rear end, weld the hinge strap 52mm back from the rear upright to allow room for the hinge pin. Equally space the remaining 2 hinge straps along the side. Tack into position, the side latch tube and packer plate, 82mm below the top of the upright (see Latch/packer details below) with the slot facing toward the rear.