Sawstop riving knife too high?

[Prashun Patel]

When I last changed blades, I noticed my riving knife was a hair proud of the top of the blade, which made non-thru cuts impossible. Adjusting it downward was a bear because of the awkward location of the adjustment nuts.

The SS tech advised me that the easiest fix was to simply grind down the top of the knife an mm or two on a bench grinder. That was an easy fix and doesn't adversely affect performance on 'higher' blades, either.

[Phil Thien]

You wouldn't, by any chance, be using a Freud blade, would you?

I noticed by Freud 10" blades are slightly smaller in diameter than the other blades I have.

[Philip Rodriquez]

The ICS is easy to adjust. Which model do you have?

[Prashun Patel]

Yup, I was using a Freud Combination blade. However, I was using previously a Freud ripping blade, which was fine.

I have the SS PCS. I thought for sure I was a boob (and still do) for not being able to adjust the riving knife. But the tech told me he had the same issue.

[Howard Acheson]

I believe that new specs to qualify for the UL label requires the riving knife to be slightly proud of the path of the blade.

[Prashun Patel]

How does that allow non-thru cuts, then? If it's true, it's obviously a ploy from the right wing Routers-for-Dados lobby.

[Philip Rodriquez]

lol, that was too funny!

[Erik France]

I believe that new specs to qualify for the UL label requires the riving knife to be slightly proud of the path of the blade.
Figure 40A.2 (Highest point of riving knife) of UL 987 shows the knife below the top of the blade with a 1mm Min. & 5mm Max. dimension.

Some of the basis for the requirement of having a riving knife was that it would not be removed as likely as a spreader would be. If the riving knife extended above the blade that would defeat some of the purpose of it.
From UL 987:



40A.2.4 A riving knife and its holder shall be so constructed that for all through cutting saw blades
recommended by the saw manufacturer, the blade diameters and for any cutting depth adjustment with
the blade set perpendicularly to the table, the riving knife shall comply with the following specifications:
a) Above the table, the radial distance between the riving knife and the edge of the blade at its
closest point to the saw blade shall be at least 0.12 inch (3 mm) and at no point shall the gap
between the saw blade and the riving knife exceed 0.31 inch (8 mm), as illustrated in Figure
40A.1; and
b) The highest point of the riving knife shall be at least 0.04 inch (1 mm) but not more than
0.20 inch (5 mm) below the highest point of the saw blade, as illustrated in Figure 40A.2.

[Kyle Iwamoto]

Mine was higher than my Forrest WWII blade. Grinder and a few seconds took care of it.
How do you like the saw?

[J.R. Rutter]

The SS tech advised me that the easiest fix was to simply grind down the top of the knife an mm or two on a bench grinder.

That's what I did, too.

[Howard Acheson]

Good info, thanks....

[David Prince]

Just smack the top of it with a hammer and you will be fine! LOL:D

[Larry Frank]

I have had the same issue with my SS PCS and had not gotten around to doing anything about it. I am very glad to hear the experience of others. I will be doing some measuring, marking and careful grinding.

[Jim Becker]

Prashun, I had a similar issue on my MiniMax slider in that I use my existing 10" blades on the machine which is designed to be able to handle 12" blades. So I picked up a second riving knife and ground down the top in the same way you mention, keeping the original available, both for use with larger blades and because it is a connecting point for the overhead collection hood when making through cuts.

[Prashun Patel]

Larry-
You don't have to be too careful. A new knife is only $15...

[Bobby O'Neal]

I'm not a SS basher at all. In fact, I'd love to have one. However, does anybody else think its annoying to have to put parts from your brand new $3000 saw on a bench grinder to make things right?

[Prashun Patel]

In the abstract, I guess you're right. But having put mine together, and gone thru the manual a couple times, and having used it for a year, I am very impressed with most everything about this saw. Perfect, it ain't, perfect enough, it is.

[Bobby O'Neal]

Makes sense. I think if out of the box you had to make modifications just to get running, that'd be a bummer. But after a year of solid convincing, I can see how adjusting the riving knife doesn't make a great saw any less great.

[Howard Acheson]

I'm not a SS basher at all. In fact, I'd love to have one. However, does anybody else think its annoying to have to put parts from your brand new $3000 saw on a bench grinder to make things right?

As I understand it, it's an issue with the blade manufacturers. It can also be an issue when the blade ground for sharpening.

[Barry Richardson]

If you have your blades resharpened, this is an ongoing problem, as each resharpening slightly decreases the diameter of the blade. Sooner or later you will need to grind down the knife if you want it to work properly. I think the problem exist with most saws that have low profile riving knives, at least the SS and PM200 which I have experience with. Just the nature of the beast I guess.

[Doug Colombo]

My new Unisaw has a release located under the front of the table to lower the height of the riving knife for a non-through cut. Very easy to adjust up or down. I think that the PM's offer a non-through cut knife as an option ( http://www.amazon.com/Powermatic-1791787-Profile-Riving-Knife/dp/B001HNM2EQ ). Not sure if SS offers one or not.

[David Kumm]

Can someone explain the necessity for the riving knife to reach the top of the blade? I use a wedge type piece in the insert for my old saw that doesn't allow for one and it seems to do as well as the full knife on my slider. I suppose a thick board could move enough that the one inch or so high wedge would not be enough but I have never sawed wood that gnarly. I understand that I am limited to 90 degree cuts but still light years ahead of nothing. Dave

[Erik France]

Can someone explain the necessity for the riving knife to reach the top of the blade? Being that a riving knife moves up and down with the blade having a knife that didn't extend up far enough could effectively create a situation where the knife would be below the table and the blade above.

A riving knife also has a curved profile creating a small clearance between it and the back of the blade. This is supposed to lessen the likelihood of kickback preventing wood from catching on the backside of the blade where the teeth are rising.

[David Kumm]

Erik, My question was really whether the knife being as high as the wood cut significantly improved the safety related to kickback or if enough height to keep the kerf from closing accomplished the same. I understand the necessity for it to be as high as the blade if it moves with the blade but most old saws are pretty easy to retrofit with a stationary piece of limited height. Wondering if that modification really improves safety or just makes me feel better. Dave

[David Cefai]

This could be a metric/imperial issue. A 10" blade is 254mm. So if Freud, or anybody else for that matter, is selling 250mm blades as 10" then the top of the blade is going to be 2mm lower. And remember that Freud is an Italian company.

[Philip Rodriquez]

FYI everyone, the ICS has an easy up and down adjustment for the riving knife... so grinding is not necessary.