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TS Kerf and Riving Knife Thickness

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Forum topic by HorizontalMike posted 07-03-2010 03:11 AM 5613 views 0 times favorited 22 replies Add to Favorites Watch
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HorizontalMike

7144 posts in 2376 days


07-03-2010 03:11 AM

Being the newbie and having “just” received my new G0690 TS, I have a question about my riving knife and the 10” blades I have purchased in advance of my TS’s arrival. I have purchased the following blades:

Craftsman Pro 80T Thin Kerf= Thickness not stated

Diablo 40T General Purpose Blade thickness is .098”

Diablo 24T Ripping *Blade thickness is .098”

NONE of these blades stated actual “Kerf” thickness.

Looking at the Riving Knife for this G0690, the following information is engraved on it:

Thickness: 0.098”
Blade Dia: 10”
Blade Body T. 0.071~0.094”
Blade Kerf W. 0.102~0.126”

QUESTION—Have I purchased all the wrong blades? And if so, what should I be looking for?

-- HorizontalMike -- "Woodpeckers understand..."


22 replies so far

View CharlieM1958's profile

CharlieM1958

16242 posts in 3681 days


#1 posted 07-03-2010 04:55 AM

The kerf on your Diablo blades is .098, which is the same thickness as your riving knife, so you are good there. Usually, when someone refers to a blade being .xxx thick, it’s really the kerf thickness that is being talked about, not the body thickness.

You will run into a problem if you try to use a thin kerf blade with a .098 riving knife. Since the kerf will be thinner than .098, the wood you are cutting will jam when it hits the riving knife. I don’t own a saw with a riving knife, but I’m guessing they must offer a thinner one you can install for use with a thin kerf blade.

-- Charlie M. "Woodworking - patience = firewood"

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HorizontalMike

7144 posts in 2376 days


#2 posted 07-03-2010 05:29 AM

Hi Charlie,
I was just reading your LJ thread on this from 2 years ago and up pops your response! Thank you for responding. While waiting for an answer I dug out my old micrometer and started measuring the blades and cutters and this is what I came up with:

CM80T Kerf=.1037” Blade=.0731”
D40T Kerf=.1025” Blade=.0743”
D24T Kerf=.1019” Blade=.0759”

So I guess this means that these clearly labeled ”Thin Kerf Design” blades are within the G0690 Riving Knife’s acceptable parameters though they are at the low end of those parameters. I guess this also means that the term ”thin kerf” lacks a definitive definition because the G0690 manual clearly warns against using them:

“Since thin kerf blades are typically the same thickness of the spreader or riving knife—and in some cases thinner—we DO NOT recommend that they be used on this saw due to the increased risk of kickback. The acceptable kerf range is 0.102”—0.126” (2.6mm—3.2mm).”

Glad to know I don’t have to go about returning them and that they will work with the riving knife in place.

-- HorizontalMike -- "Woodpeckers understand..."

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knotscott

7210 posts in 2838 days


#3 posted 07-03-2010 05:34 AM

As long as the blades cut a swath at least as wide as the riving knife, they should work, but it sounds like it’ll be close.

I question the need for thin kerf (TK) blades for a 3hp saw. I’ve been a supporter of 3/32” thin kerf blades for smaller saws, but you’ve got ample power to spin the full kerf blades 1/8” (0.125”), which are inherently more stable. The wood savings is typically minimal, so there’s less incentive to use TK’s with a saw with the power of the G0690.

To be on the safe side, I’d seriously consider returning that set and getting full kerf blades instead of TK.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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CharlieM1958

16242 posts in 3681 days


#4 posted 07-03-2010 05:49 AM

I have to agree with Scott in that I use a full kerf Forrest Woodworker II for most everything I cut on the table saw, and just don’t see a whole lot of advantage to thin kerf blades.

-- Charlie M. "Woodworking - patience = firewood"

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HorizontalMike

7144 posts in 2376 days


#5 posted 07-03-2010 06:29 AM

Other than the CM blade, I didn’t know the Diablo’s were TK at the time of purchase. That was the only thing available at the HD, my local building supply. That and I’m not ready to drop ~$150 per blade for the Forrest WWII.

Being the newbie, I am just now becoming aware of the need to match kerf & riving knife on the TS. Chock that one up to the learning curve.

For now, since these blades do fall within the acceptable parameters of Grizzly’s recommendations and are at least .040” larger than the riving knife, I will keep these and upon replacement probably move to thicker full kerf blades once I burn through these first ones at $40 a piece.

-- HorizontalMike -- "Woodpeckers understand..."

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ChrisCarr

196 posts in 2361 days


#6 posted 07-03-2010 07:49 AM

I know some may say this is dangerous but if you use featherboards (attached to to the fence’s side)on rips and a sled on crosscuts its unlikely you will get your wood binding on the blade so you could work without the splitter/riving knife on.

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knotscott

7210 posts in 2838 days


#7 posted 07-03-2010 12:58 PM

I wouldn’t drop $150 for any blade either Mike. Here’s some ”full kerf” food for thought though… in the $150 per set range that are all up to the task and great values.

CMT 24T FTG rip blade – 201.024.10 – ~ $38 shipped from Holbren with “BT310” discount code.

Oshlun 24T ATB rip blade – SBW-100024, ~ $25 shipped from Holbren with “BT310” discount code.

Infinity 24T FTG ripper – 010-024. On sale for $46 from Infinity (free s/h over $100).

Delta 40T ATB blade – 35-7657, $28 shipped from Cripe.

Infinity 50T ATB/R “Combomax” – 010-050. On sale for $60 from Infinity (free s/h over $100).

Oshlun 40T ATB SBW-100040. ~ $26 shipped from Holbren with “BT310” discount code.

Infinity 80T Hi-ATB “Ultrasmooth” – 010-080. On sale for $70 from Infinity (free s/h over $100).

CMT 80T Hi-ATB blade – 210.080.10, ~ $60 shipped from Holbren with “BT310” discount code.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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HorizontalMike

7144 posts in 2376 days


#8 posted 07-03-2010 02:06 PM

Geez, adding to the confusion, as I look more closely at the Grizzly G0690 ”accessories” webpage I see a number of ”thin kerf” blades being recommended for this particular TS being advertised and sold BY Grizzly (especially the DeWalt .071” blades):

http://www.grizzly.com/products/10-3HP-220V-Cabinet-Table-Saw-with-Riving-Knife/G0690/accessories

So what gives? Is Grizzly just pulling a major CYA move in the manual or what when it warns against using TK blades?

And regarding Chris’s recommendation about using featherboards, I purchased a couple of the yellow ”board buddies” from Grizzly for use on the G0690. They seem to be the techy version of featherboards:

http://www.grizzly.com/products/Board-Buddies-For-Table-Saws-Yellow/G2370

-- HorizontalMike -- "Woodpeckers understand..."

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charlie48

248 posts in 2632 days


#9 posted 07-03-2010 02:08 PM

Mike,
Charles Neil has an offer on his web site for Saw Stop blades,40 tooth,and 80 tooth both with .125 kerf, and at a good price. Charles has been using one for a few weeks and likes it, probably worth looking into.

-- Charlie............Only time will tell if it was time well spent.

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CharlieM1958

16242 posts in 3681 days


#10 posted 07-03-2010 03:46 PM

Mike: Taking a look at the saw specs, I noticed that the riving knife is advertised as “quick release.” I’m assuming that means you can easily remove it for certain situations, like using a thin kerf blade. That would explain why they advertise thin kerf blades for the saw.

There are aftermarket splitters you can use with a zero-clearance insert. The one thing you can’t do is use a blade with a kerf that is thinner than your attached riving knife.

-- Charlie M. "Woodworking - patience = firewood"

View HorizontalMike's profile

HorizontalMike

7144 posts in 2376 days


#11 posted 07-03-2010 05:17 PM

Charlie,
That makes sense about the ”quick release” feature with regards to the different blade offerings, though I wonder why information like that doesn’t get spelled out anywhere. It sure helps to have LJs to help fill in those blanks!

Back to my personal measurements from above, plus a new measurement:

CM80T Kerf=.1037” Blade=.0731”
D40T Kerf=.1025” Blade=.0743”
D24T Kerf=.1019” Blade=.0759”

Riving Knife actually measures out as 0.97” thick (measured multiple points and still came within <.0002” of .097” for RK maximum thickness. I would think that should give me a bit of additional breathing room (safety) with regards to using the above blades as measured (blade kerfs are ~.005” wider than RK). Yes?

-- HorizontalMike -- "Woodpeckers understand..."

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CharlieM1958

16242 posts in 3681 days


#12 posted 07-03-2010 05:44 PM

I think you’ll be okay with those .098 blades. It’s not really like you would be in danger by trying it…. the only downside would be if you experienced too much friction going past the knife, making it difficult to feed the wood through.

Since you are new to this, you should definitely try a .125 kerf blade as well so you have a basis for comparison.

-- Charlie M. "Woodworking - patience = firewood"

View HorizontalMike's profile

HorizontalMike

7144 posts in 2376 days


#13 posted 07-03-2010 06:07 PM

Thanks Charlie, I will definitely try the .125” blade at some point.

Any ideas why my measurements for the Diablo blades are not even close to the published .098” thickness (I get ~.102”)?

-- HorizontalMike -- "Woodpeckers understand..."

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CharlieM1958

16242 posts in 3681 days


#14 posted 07-03-2010 06:36 PM

I would have thought the manufacturing tolerances were closer than that, but let’s face it… 3 or 4 thousandths is not a lot in woodworking terms. Personally, I don’t trust my own use of measuring devices to get me any closer than that.

-- Charlie M. "Woodworking - patience = firewood"

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CharlieM1958

16242 posts in 3681 days


#15 posted 07-03-2010 06:54 PM

As a matter of fact, I just went out to the shop and checked my Forrest .125 blade. The best reading I could get with my inexpensive digital readout calipers was .119, so go figure.

-- Charlie M. "Woodworking - patience = firewood"

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