A rotary vise is one type of fly tying vise, which is a tool used in flyfishing. Fly tying vises have jaws that hold the hook securely while the fly tying piece wraps the thread or other material needed to create a fly. The jaws of a rotary vise rotate with an extension that has a horizontal axis of rotation, unlike conventional vises in which the jaws rotate around their own central line. The hook must be able to turn fully more than once in the same direction without stopping, but should also be able to turn both clockwise and counterclockwise.
Many flyfishers who have tried a rotary vise find it has several advantages over a non-rotary vise. One advantage is that the fly can be rotated any way, allowing it to be inspected from all sides. The fly turning so effortlessly makes it easier to secure almost any fly material. It is typically easier to tighten or loosen the hook holding mechanism since the jaws turn as well. The vise also has a rotation lock that completely locks the extension, allowing it to work as a non-rotary vise.
When it comes to adding extra material, the rotation is a great plus. A rotary vise works well for dubbing, which is simply applying fur to thread and creating a fly body out of the wrapped threads. The dubbing is wound around the hook shank by rotating counterclockwise.
Rotating the vise helps greatly when adding any material that does not easily stay straight. This method can be used to add material with or without a bobbin cradle, which allows the bobbin to rest between tying operations. Adding ribbing also works must faster with a rotary vise. If the ribbing starts to get uneven or caught together, a simple turn in the opposite direction can correct the problem quickly.
While the ability to rotate the vise has some advantages, a few things need to be considered in order to get the most out of a rotary vise. Whenever the vise is turned, the thread and material will wind on or off the hook, depending on the direction it is turned. This means that more turns of thread will need to be added before rotating or removed after rotating. If not, either tied thread will loosen or extra thread will be added. This issue can almost always be avoided by adding a bobbin cradle to the vise, which will hold the thread away from the fly.