I was looking at different plans for making a workbench that, one day, I will have the space and materials to make. One sets of plans I ran into had a board cut and recessed with a handle.
I have seen lots of bench plans but can't find more than this one using an insert (perhaps insert is a colloquialism?). Sure it makes a wicked paddle but what would the use of this space be?
Image from http://www.shavingsandawl.com/
It functions as a plane stop, for planing cross grain with hand planes. If you don't plan on using hand planes extensively, it isn't necessary. If you do decide to use hand planes, you can get the same effect from bench dogs, or even just clamping a board to the bench.
My preference is still more toward a Roubo style bench. It is more versatile and actually easy to build. I built a mini version just using construction grade lumber from my local Home Depot.
If you search Youtube for split top roubo benches you will find many examples of this bench feature in use. The insert board is loose in the gap and designed to be flush when oriented with one side up and as a bench stop when reversed so that the other side of the insert board is up. The insert gap provides space in which two bench slabs can expand towards the middle while keeping the outside edges firmly anchored and flush with the legs. This flush leg/top feature is very useful for clamping wood to the sides and top. The center infill board is often made of two pieces of 1/2" thick continuous wood with a center 1/2" spacer. This creates long slits in which you can place chisels, saws and other tools while working, a much better option than having them roll off the top. Finally, if the center insert is removed you have a 1 1/2" gap in which you can pass bar clamps to clamp something down to the top slabs from the center. This is a much better option than drilling more dog or hold down holes for rarely needed clamping positions.
I would find such a feature useful as a stop, in conjunction with the vise. Rather than having to put in a bench dog at the end of a board to plane, you could just raise up the insert a bit.
