The best sander for board edges is an oscillating drum sander. It will keep the edge square to the board's surface as you sand the edge, but it would be better if you could improve your saw so you wouldn't need to sand or rout the edges very much, if at all. A good, fine tooth carbide blade is my first suggestion. A zero clearance insert is my second suggestion. The zero clearance insert holds the edges of the cut from lifting and splintering as the blade teeth exit from the wood.
If your saw is a table saw you can make an insert from wood to replace the existing insert in your saw, but make it without a blade hole. Then install this new insert in the table and then slowly raise the saw blade while it's running to cut a saw slot through the insert at the exact width and position needed by your saw blade. If the blade won't go low enough to do this you can install a smaller diameter blade of the same width to make this first cut and then replace it with your full size blade.
For a hand held circular saw you can also make a zero clearance insert type base. You will need a piece of thin plywood or lexan plastic the same size as the base of your saw (don't use plexiglass as it shatters easily). You can attach it to the base of your saw by bolting it in place using flat head screws with the bolts recessed into the insert base. One bolt toward the front and one toward the rear should be sufficient. You will need to manually retract the blade guard and raise the blade as far as possible for this installation. Once the insert base has been installed , you can plug the saw in and run it while plunging the blade slowly and completely through the new zero clearance insert base. Then release the trigger, let the saw come to a stop, and unplug it. Now you will need to mark a clearance area where the blade guard needs to swing down through the zero clearance base, but do not mark the front area where the blade teeth come up through the insert. Only mark for removal the area that is actually needed for the blade guard to operate freely. You may need to remove and re-install this zero clearance base a few times to be sure that you have marked only the area for the blade guard to move freely. Now remove the insert base and cut out this marked area. The accuracy of this cut is not really important as it's only to let the guard operate. The remaining hole should look like a rectangle with a 1-2 inch saw cut in the leading edge. Re-install the insert base, make certain that the blade guard operates freely and you can raise and lower the saw blade to it's limits without binding. You are now ready to use it. As the blade teeth rise up through the wood, both sides of the saw cut will be held down by this zero clearance base and the wood will cut cleanly with very little splintering.
My shop is small so I can't cut full sheets of plywood on my table saw. I use my circular saw with a thin kerf fine tooth carbide blade and one of these zero clearance bases with a straight edge guide to break down my sheets of plywood outside my shop, then bring the parts inside for final milling. The circular saw cut edges are just as smooth and straight as if I had cut them on my table saw and little, if any, sanding is ever required.
Central North Carolina
Last edited by CharleyL; 04-28-2012 at 08:18 AM.