This clamps I have made to fix thin flat work pieces on the milling table. When a work piece is to long and thin it will be bend in the milling vise during machining. These are also useful to fix wider parts immediately when these not fit in the milling vise.
The clamps are fixed on the milling table with bolts and T nuts. The work piece is lying on top of the clamps end fixed with the side plates.
You can download the drawings for your own use