Two 3" long 1" pipe nipples are required. Black pipe would work but if galvanized pile is available it will hold up a little better to corrosion.
First order of business is to clean them up. Use a solvent first like Alcohol, Mineral Spirits, Paint Thinner or?? to clean off dirt, grease and oil. Then second pass put under hot water faucet with a brush and dish washing detergent.
Later on in the build we will be putting Friction Tape onto these nipples and adhesion will be a lot better when they are clean.
Be careful now as the threads are sharp. When screwing into the axle receptacle before the Friction Tape is applied, wrap with paper towels or a rag to prevent cutting your hand.
