What You'll Need

• To make your own homemade trailer dolly you need a few feet of steel tubing. A good size, if you're using round tubing, is about 1.25 inches in diameter. If you use square tubing it should be about 1.5 inches square. A wall thickness of 1/8 inch is adequate for either round or square tubing. You'll also need a piece of 5/8-inch round stock for the axle, two wheels and tires, a trailer hitch ball and a short piece of one-inch round stock or pipe for the handle.
  
  

Making a Tow Dolly

• Start by making the handle assembly. Cut two pieces of the round or square tubing. Make one about five feet long and one approximately two feet long. Weld them together in a "T" shape, with the short piece being the cross bar. Center and weld the one-inch pipe or round stock to the other end of the five-foot piece for a handle. This is a good time to also weld the 5/8" round stock axle to the two-foot long crossbar. Make the axle long enough to allow the wheel to fit with a flat washer on both sides of the wheel and drill a hole through each end of the axle for a cotter pin. Install the wheels on the axle.
  
  Next, measure the distance from the trailer coupler to the ground when the trailer is off the vehicle and sitting on its jack. This measurement, minus the length of the hitch ball is the length of the upright for your trailer dolly. For example, if your trailer tongue to ground measurement is 20 inches and your hitch ball is three inches the length of the tubing for the upright is 17 inches. Weld the hitch ball to the top of the upright.
  
  Welding the upright in place is easiest with a helper. With the axle centered under the trailer tongue have your helper hold the handle at a towing angle while you tack the upright in position between the hitch coupler and the dolly crossbar/axle. Jacking the trailer higher first makes this task easier. Insert the hitch ball into the coupler and tack weld the upright in place after ensuring that it is straight up and down. After final welding of the upright and a paint job, your homemade trailer tow dolly is complete.