Hi Byron, As has already been mentioned the space is the same distance as the cutter being used, which in my case was 1/2". I just placed another 1/2" cutter between the rail and cutter and clamped it there. With a little adjustment and a few trial cuts it is easily set up. The hardest part was cutting the rail to be a perfect 1/2" along it's length, have to be very accurate with this. I would post some pictures of it but the server is down on my photo hosting site at the moment, will post some later. :wink: