Above is a Binding Groove Cutter or perhaps a Gramil exquisitely crafted and photographed by Christophe Mineau.
Christophe Mineau is a kindred soul and an amazing craftsman who is nine years younger than I am and a hundred years ahead of me in craftsmanship! His musical instruments are a delight, his tools a wonder and his methods are solid and clever. His website is in French and English, so you can enjoy his work in two languages. There is really no point in my going on and on here, although there is a lot to go on and on about. Go to his site and enjoy!