Step 14: Finishing the cart
*Drill a 1/8" starter hole 1/2" from the end of the pulling arm, and enlarge to 3/8". This hole should be as close to vertical as possible.
*Crush the end of the pulling arm slightly around the bolt hole so a 3/8" nut just slides inside. Slide a 2" long 3/8" bolt through the arm, from the top to the bottom, threaded through the bolt inside the arm. Slip a 3/8" split-ring lock washer on, and then thread another 3/8" nut onto the end of the bolt and tighten it until the tube is crushed around the interior nut. Thread one more 3/8" nut onto the bolt. Make it tight. Option: Braze the nuts and bolt together, and to the arm.
*Take a 3/8" wing nut and braze a 2" long piece of scrap metal onto the two wings. Use some of the rod from the hitch, or whatever you find. This will be the nut that attaches the cart to the bike, and the wing nut extension allows removal without tools. (Alternative: use a 3/8" nut with a wrench.)
*Attach the wheels to the cart. If there are quick release skewers, put the levers on the outside of the cart.
*Paint the joints of the cart with an outdoor metal paint and/or primer. You don't need spray paint. Any anti-rust brush-on paint works. Paint the hitch too, but not the inside of the nuts (clamp hitch). Remove the ball joint before painting the hitch.
*Add a bed. Use 1/2" plywood that is 19" by 38". Use any kind of clamp to attach the bed to the ribs. Plumbing or conduit clamps work. Sheet metal strips with punched holes are cheaper but more work. You could try plumbers' tape, screwing through the holes into the plywood. Cut slots in the plywood to fit the tubes where they curve. This part can be any kind of creative expression. Metal, driftwood, plastic, canvas, plywood, rope, glass--some ideas are better suited to certain applications.
*Make tie-down straps out of old bicycle tubes, with the valve cut off. Use bowline knots to attach them to the main frame.
*A nice option: Add something unique and special to the cart. My personal favorite is a pole with space for art and signs.
"One less car"
"Yes, I'm moving by bike"
"One less car; make it two?"