The basic idea makes sense, support the workpiece near the cut to prevent tearout. But then the details get confusing. Seems to me there is very little cutting going on at the sides of the blade between the arbor and up to just behind the teeth, so does having zero clearance there help any? Now if the cutting is happening at the very end of blade (and maybe a little ways on either side), then it would seem you would need a different zero clearance insert for each height of cut as well as each blade tilt. If I cut a 3” thick piece of stock, the blade will be high, if I lower the blade to cut a piece of ¾ ply, then the insert will no longer be zero clearance where the cutting is actually occurring. Seems it would get expensive and confusing to have many different inserts for different heights. What I am missing here? Do you just leave your blade high for all through cuts?
James