I've used those "chucks" when using a spoke shave or even when chamfering the corners with a plane and the "dog clamp" (auxiliary clamping jaw) for hand planing longer boards. And that "drilling machine holder" in the upper picture that Duckie's picture showed can be used like a drill press. See lower right below.
There are a bunch of other configurations shown in the manual including ways to tilt and pivot the jaws.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
