I have made tools like I think you're describing, not sure what size pipe you're working with. I cut the jaws out of a vice grip and welded a short section of pipe that I cut lengthwise to where the jaws had been to make two half round jaws. I modified a couple of channel lock type pliers by doing the same. If you have access to a welder and metal cutting tools, it's not a big project. You could line the pipe pieces with a grippy rubber material if necessary.