Should a Rip Fence and Blade Be Parallel?
Issue: Issue 307
Posted Date: 8/14/2012
I have an old DeWALT table saw and I have a question about fence adjustment. Should the fence be as parallel to the blade as possible, or should it toe into or away from the trailing edge of the blade? The blade mount cradle is not adjustable on this old saw. I do use a newer fence that holds its adjustment real well. When I saw a board without a featherboard, unless I am really careful the board against the fence comes out with a slight convex. - Dean Brumley
Chris Marshall: Some woodworking experts advise that a rip fence should be adjusted so that it toes out and away from the blade by about 1/64th inch or so. The reasoning is that this creates a widening "tunnel" between the fence and the blade and reduces the chances of the workpiece getting wedged in between the two, which could create a kickback situation. I don't follow this practice. My fence is parallel to the blade. I think the safer precaution against binding is to have a riving knife or, on an older saw like your DeWALT, a splitter behind the blade when ripping. A riving knife or splitter creates a mechanical divider to ensure that the kerf between the workpiece and the offcut stays open. Under no circumstances would I toe a fence into the blade. That would create a tunnel that gets narrower on the outfeed side of the saw and forces the wood against the blade laterally ... a bad idea. In that situation, a kickback is almost guaranteed to happen sooner or later.
I suspect that that the convex edge you get when ripping without a featherboard is happening because you are trying to keep the workpiece pressed against the fence when it actually wants to drift away from it. The blade is pulling the wood away from the fence, which is probably toed out. A featherboard forces the cut to behave, but the toe-out probably leads to ragged cuts or burning on the offcut piece. Adjusting your fence so it's truly parallel to the blade should correct this problem and straighten your ripped edge.
Rob Johnstone: For regular ripping operations, table saw fences should be perfectly straight and perfectly aligned — parallel — with the saw blade. (No toe-in or toe-out.)
Tim Inman: Sometimes a fault of old tools is poor engineering; sometimes the old tools have faults because of abuse they've suffered through the years. It is hard to know which might be your trouble without seeing the tool. As to your other questions: In my shop, the fence is parallel with the saw blade. If anything, I DO NOT want the fence to toe in and pinch the trapped off-cut piece between the blade and the fence! This is a safety kickback accident waiting to happen. Some European saws actually use a "half-fence" which stops at the center of the blade. This means there is no fence or contact behind the blade -- where the off-cut could be trapped. It is not found in the USA. There is usually enough "slop" in the bolt holes that fasten the table top to the cabinet or trunnions below to allow the miter gauge slots to be perfectly aligned with the blade track. This, in turn, enables the rip fence to also track perfectly after adjustment. I highly encourage this setting.
Now, having said all this, it was not uncommon to find some of the old-time cabinetmakers setting their fences to slightly pinch the off-cut piece. My father is one of them. He likes it so the piece will "self-feed" back out when he makes his cuts. Frankly, it scares the living daylights out of me, and always has (language modified for publishing in polite company!). He still has all 10, though, and in his late 80s, still works. DO NOT DO THIS! Why? It is also not uncommon to find old-time cabinetmakers who have a stub finger or two.... 'Nuff said.