Take axle measurements from where the axle tube meets the leaf spring mounts, then cut the axle in half using a saw.
Slide the axle halves over the 3 foot-long sprinkler pipe and weld the axle onto the pipe.
Cut two pieces of 18 foot-long angle steel and weld these onto the sides of the car tow dolly to create a base for the car tow dolly. Create two pieces of angle steel that will fit at the top and bottom of the car tow dolly. This measurement will differ depending on the axle. Weld these two pieces to the sides.
Cut a piece of box steel 4 foot long and tack weld this piece in the center of the cradle.
Cut two 12-inch pieces of 2x3 steel. Place one piece on top of the other and slide it out 6 inches, then weld the pieces together. Weld this piece onto the 4-foot piece created in the previous steps and extend it from the dolly with at least a 6-inch overlap.
Cut 2 27-inch pieces of 2x3 and attach these under the tongue and cradle.
Attach the trailer coupler to the tongue with high-quality bolts or weld it to the tongue.
Cut the 2x12 piece of wood in half and cut two pieces of angle steel 12 inches long. Attach these angle steel pieces to one end of each plank with carriage bolts. Tighten bolts with wrench.
Attach the tie down straps and fenders to the trailer.
Mount one light to each fender. The trailer lights will differ depending on the kind of lights you purchase. It is important to install the trailer lights as indicated with the lights. Make sure to wire them correctly.