I have a couple of the sliding ring hand vises used by jewelers and watchmakers. They do not hold the hook very well. The other popular jewelers or watchmakers vise had a thumbscrew or a wing nut. These work much better. I am especially fond of the Eclipse vise made in Shefield England. A few early fly vise makers incorporated Eclipse vises in their fly vises. I plan to publish a book within the next six months on vises. If interested PM me and I will send you a note when the book is available.

Ed