I only have two sets of tongs, but I made both from lawnmower blades. Here is a photo and how I made them...
1) I first took an old blade and cut it in half length way. I use a skill saw with a metal cutting disk.
2) Then I forged the edge ends of the two pieces down square.
3) Next I figured out where I wanted my pivit, and I heated the blade and punched my holes.
4) I then heated the end and put a 1/4 twist into it.
5) To join the two pieces, I put a bolt through the hole, added a nut to it, and cut the excess bolt off. I put the tongs back into the forge and got the bolt red hot and beat on it to make it swell up in the hole.
6) I finished by heating the end of the tongs and forming the mouth of them around the horn of my anvil.
These were the very first thing I tried to forge. They don't look that great, but they have held up well. They will not be as strong as good tongs, but for the small knives that I make, they work great.
Hope this helps. -chris