I bought the vacuum plates from Oak Park last month. It comes with a little plastic channel that you screw into the bottom of your table and it opens to the exact size of a vacuum hose. I am not that happy with it. I find the channel gets in the way of the router and the fences get in the way of the holes in the plate. It only really works for certain applications.
I built a holder that allows me to clamp my vacuum hose to my table top and can move it to where I need it. Way more efficient than the vacuum plate system.
I built a holder that allows me to clamp my vacuum hose to my table top and can move it to where I need it. Way more efficient than the vacuum plate system.