Align riving knife on a Sawstop PCS

[Johnny Barr]

The manual describes aligning the left of the blade flush with the left of the RK and yet many youtube videos and woodwork forums describe aligning the right of the blade (closer to the fence) flush with right of the RK which makes sense as it would help keep the stock against the fence

Which is it? Align flush left away from the fence or flush right towards the fence?

[Jim Becker]

Personally, I'd choose the fence side since that's where there is risk of binding.

[Johnny Barr]

That's my feeling too, Jim but I'm curious as to why Sawstop want it flush aligned on the non fence left side of the blade. Incidentally out of the box it was aligned on the non fence side, left of the blade.

In fact I remember on my old table saw I bought the Microjigs MJ splitters and they were aligned closer to the fence which they describe as having a featherboard effect which makes more sense. I have emailed Sawstop

[Johnny Barr]

Just got an email back from Sawstop and they said the riving knife should be centered within the kerf which contradicts what it says in the manual (page 78) where it shows a straight edge flush against the left of the blade and left of the RK. My saw is cutting well and I'll probably end up leaving it as it is but I'm curious as what is considered the best and safest way of aligning a RK

Boy am I confused now!

[David Kumm]

The knife should be centered in the kerf because ideally, the knife should be thicker than the blade plate but less than the tooth. Dave

[Ben Grefe]

The left edge of the blade is fixed against the arbor. No matter how wide the kerf of your blade, the left edge of the blade is always going to be in the same place in space.

The right edge edge of the blade will move depending on kerf width. If you align the riving knife to the right edge of a full kerf blade and then switch to a thin kerf blade, the rising knife might be too close to the fence and cause a jam.

I suspect Saw Stop assumes most people are going to set the riving knife once and forget it. Their instructions probably reflect that. If you never plan on switching blades, then align it right. Otherwise I think aligned left is safer.

[Johnny Barr]

I watched this video https://www.youtube.com/watch?v=UZc_HncMse4&t=7s . Microjig have a new product called arbor shims where you can align the riving knife on the right and use shims when switching to a different (thinner) kerf blade. Not sure about the value and suitability of this product but it was this interesting video that made me think right aligned is better.

[glenn bradley]

I center it. Blades can have different widths of kerfs but the center is still the center.

[Randy Heinemann]

Like David Kumm in a previous response, I center the riving knife on the blade as close as my eyesight will allow. I believe the only purpose of a riving knife is to ensure that the kerf does not close on the blade body, thus pinching the blade and causing the blade to bind in the wood. I don't believe that part of the riving knife's job is to hold the board against the fence. Sawstop's manual also indicates the minimum kerf thickness that they say will work with the included riving knife. I wanted to use a thin kerf Freud blade, but the kerf is just shy of Sawstop's specs. While a few thousandths might not make a difference, the kerf would, in fact, be just a little thinner than the riving knife, which defeats the purpose of the riving knife. I do not believe that I have ever read anything that indicates aligning the riving knife with either fence or non-fence side of the knife is the correct alignment.

[Frank Pratt]

I believe that the most important function of a riving knife is to keep the piece from straying away from the fence and into the blade where it could be kicked back. Particularly when the far end lifts a little, as can happen when due care is not taken.

In my pre-riving knife days I had lots of cases where the wood pinched the blade & the only thing that ever happened was smoke & sometimes a stalled blade.