Re: Bar-B-Que Grate ... what metal?
I made one of those about 6 years ago. I drove an old metal fence post into the ground by my fire pit. Then I got a piece of round tubing that would fit over the fence post. On the round tubing I welded my bracket (1 1/2" angle iron) to hold the grate assembly that would swing over the hot coals. At the end of the bracket I drilled a 1/2inch hole for a piece of all thread to go through.
My grate assembly I got two charbroiler grates from a used commercial kitchen supplier. I made a frame to hold the grates with 1 1/2" angle iron. On each corner of the grate I welded angle iron about a foot long pointing up (like an upside down table). There I made and "X" brace connecting the corners. Where the "X" is in the center, I drilled a 1/2" hole.
To connect the two pieces, the swivel post and grate assembly, I used 1/2" all thread to go through the holes. BTW, I welded the all thread to the grate assmebly's X brace. On the swivel post I welded a nut on the top side of the swivel bracket. I left about 2' between the bracket and grate assembly with the all thread. I left about 1' of all thread sticking up from the bracket. On top of the bracket, I welded on an old handle from a winch off a boat trailer. This way I can crank the grate assembly up or down as needed. If the fire/coals are too hot, I can swing the grate off to the side to flip the food or to raise/lower the grate. It makes it nice to rotate the grill over the fire to distribute the heat more evenly. Works well. If I had a camera I would take a pic of it for you.