KenH put this up at the beginning of the post.
I was asked about this just yesterday by a fellow pinhead so I made him one. This is about the 10th one I have made for other people.
I believe this was a Clay inspired tool to start with. Here you can see one in it's package new and the one I modified. There are two ridges meant to hold a chain link in position. I ground those out with a Dremel by trial and test until I got the exact depth to remove and re-install the roll pin. Only remove as much of the material as necessary.
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