Riving Knife ? Go690 saw

[Jeff Miller]

The book says to only use full kerf blades but the riving knife and splitter measure 3/32" or 0.095" which is exactly the same width as my thin kerf Freud combination blade (measuring the width of the teeth).

The book says that the riving knife is 0.095" thick(which is what I got when I measured it).

So why do I need a wider kerf blade?



JEFF:D

[Rick Moyer]

Well, I don't know for sure, but, if they are EXACTLY the same width and you have the riving knife just slightly closer to the fence (i.e. not perfectly alligned), you will pinch the pc. between the knife and the fence. I suspect they want some margin of error.

[Matt Stiegler]

You could call Grizzly tech support and ask them that question. But I agree with Rick.

[Floyd Mah]

A riving knife would have several functions. One is to keep the workpiece from bouncing off the fence and then crossing the rising rear teeth of the saw blade. This would turn the workpiece into a flying saucer travelling faster than you could react. If your workpiece could get past the riving knife, despite the kerf being the same as the blade, you would probably not have a problem.

If the workpiece binds, then you are creating a hazardous situation. This happens if the kerf closes behind the blade. Then you are facing a workpiece stuck to the riving knife and would need unusual effort or manipulation required to complete the cut.

The kerf may close anyway even with a well-matched riving knife, but you are hoping that the riving knife will cause this to happen far distal to the teeth of the blade which may otherwise cause a kickback. A riving knife slightly thinner than the blade will be OK since any contact of the workpiece with the teeth will probably be a grazing contact. This minimal contact would usually not be enough to let the blade really grab onto the workpiece. A riving knife dimensioned too close to the blade's width would increase the likelihood of binding. This is the reason why the manufacturer recommends a full width blade. Your other choice would be to have a riving knife made that is slightly thinner than the kerf produced by the thin-kerf blade.