Well this is probably another one of my many silly questions. But. In anticipation of building a whole new work bench,I was changing my existing work bench around to accommodate a Jorgeson vise. In 25 years I have not had a real woodworking vise. It's about time, I think. So I slid the top over 12" so I would have an 18" overhang instead of just 6". That increased the over all length to about 84". (Trying out the size) I noticed after installing the vise that the screw and guides actually were at least 1 1/2" below the top. Other than the top 4" for screw and guide clearance why are many of the bench cabinets so much shorter than the tops. It seems like a waste of valuable storage space. If I were to build a modified shaker or rubo bench, what reason would there be to extend the top so far beyond the cabinet base?