# Thin or full kerf?



## hawkeye10 (Feb 18, 2015)

My saw is a 10" Jet Pro Shop with a 1 3/4 HP motor. I am using Freud blades the good ones not the ones they sell at HP. So what is your opinion on which kerf blade I should use?


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## Steve Neul (Sep 2, 2011)

Freud makes a lot of different blades for different applications. We would need to know which blade you are asking about and what you are using it for.


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## Gary Beasley (Jan 21, 2009)

Full kerf is good for stability if you need really accurate cuts. Thin kerf is good if your saw bogs down frequently while cutting, but can have issues with flexing on occasion. Also good for cutting down expensive wood for pen blanks.


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## woodnthings (Jan 24, 2009)

*I am running all thin kerf blades*



hawkeye10 said:


> My saw is a 10" Jet Pro Shop with a 1 3/4 HP motor. I am using Freud blades the good ones not the ones they sell at HP. So what is your opinion on which kerf blade I should use?


As suggested, if your saw is bogging down when ripping thicker stock, over 2 inches, then it's time to switch to a thin kerf. As long as you understand when to use a 24 T, a 40 T and a 60 T blade you're all set.
24 teeth for ripping, 40 or 50 for general purposes, and 60 teeth for crosscutting and plywood. I have an 80 tooth for mitering hardwood frames, but that's about all it's used for.

FWIW, I do use the Diablo thin kerf blades from Home Depot, and there is a 50 tooth and a 24 on the saws right now. :smile2:


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## hawkeye10 (Feb 18, 2015)

Steve Neul said:


> Freud makes a lot of different blades for different applications. We would need to know which blade you are asking about and what you are using it for.



Steve I have been using the Freud Fusion blade and have both kerfs. I do have a Freud rip blade but rarely use it because I can't see much if any improvement in cut quality. 99% of my cutting is one inch and less.


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## 35015 (Nov 24, 2012)

hawkeye10 said:


> My saw is a 10" Jet Pro Shop with a 1 3/4 HP motor. I am using Freud blades the good ones not the ones they sell at HP. So what is your opinion on which kerf blade I should use?


Hi Hawkeye,

I think you have stumbled onto one of the anomalies of modern woodworking in the last two decades, and what trade with Japan, and metallurgy has garnered us all in that time...

Saw motors, and saw sizes have gotten lighter and less robust in most of the consumer, and even commercial market. As such, thinner kerf blades with better metals and tooth design have give us the ability to cut deeper and in harder woods with less motor power...and...really thin blades!

For light machines, and such, a good quality thin kerf blade is almost impossible to beat. Speed of feed has to be slower often or more passes made to get through something really hard.

I admit, we are setting up our "new" very old North Field now with 16" blades instead of 18", are very heavy kerf blades...but...they track so straight and true with full depth cuts in hard woods, that going back to the more "economy sized" saws to do work is not only unproductive...its frustrating. They do this too without a riving knife which I find an absolute must have for thin kerf blades. These big Olivers, North Fields, etc are worth the effort in acquisition if really into woodworking and using power tools...especially for production work...

Regards,

j


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## Steve Neul (Sep 2, 2011)

The 40 tooth blade is a good general purpose blade that works fairly well for plywood and can cut hardwoods good. I don't personally care for the thin kerf blades. If you can keep a thin kerf blade good and sharp it's alright but if you use one until it gets dull and try ripping hardwood the thin kerf blade easily heats up and warps. Then the mistake most people make when they warp a blade is to immediately shut the saw off. The blade cools off and stays warped. If they would leave the saw running until the blade cools the centrifugal force of the blade turning normally will straighten the blade back out.


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## Toolman50 (Mar 22, 2015)

I’ve enjoyed the thin kerf blades. 
Blade prices have actuallen fallen over the years. 
The Carbide seems to stay on the blades better than in the earlier years of carbide.


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## Terry Q (Jul 28, 2016)

I have the same saw and only use full kerf blades, I have had no issues.


In woodworking there is always more then one way to accomplish something.


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## GeorgeC (Jul 30, 2008)

As you can see from the comments, it is pretty much a personal choice.

George


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## Woodknack (May 12, 2017)

I don't find any difference between the Asian and Italian Freud blades, both are middling quality and quality control on the Italian blades has taken a nosedive in recent years. Rip blades require less power so I would go flat top, full kerf. Thin kerf on combo & crosscut. Probably doesn't matter on a GP.


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## Steve Neul (Sep 2, 2011)

hawkeye10 said:


> Steve I have been using the Freud Fusion blade and have both kerfs. I do have a Freud rip blade but rarely use it because I can't see much if any improvement in cut quality. 99% of my cutting is one inch and less.


The 40 tooth blade does very well ripping however when ripping hardwood the fewer teeth you have the easier it cuts. The best blade I ever used for ripping hardwood was a fiber cement blade that only had about 6 teeth on it.


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## hawkeye10 (Feb 18, 2015)

Steve Neul said:


> The 40 tooth blade does very well ripping however when ripping hardwood the fewer teeth you have the easier it cuts. The best blade I ever used for ripping hardwood was a fiber cement blade that only had about 6 teeth on it.


Steve, that is a new one on me. I will have to try it.


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## Steve Neul (Sep 2, 2011)

hawkeye10 said:


> Steve, that is a new one on me. I will have to try it.


I was working someplace where we were ripping a lot of 8/4 hard maple and having a hard time with it. The guy I was working for had a representative from a blade company come out to the shop for a solution and they set us up with a fiber cement blade. I didn't even know what that kind of blade was intended for at the time. All I knew is it only had six teeth on it and it cut that 8/4 like a 26 tooth blade cut 4/4.


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## woodnthings (Jan 24, 2009)

*How so?*



Woodknack said:


> I don't find any difference between the Asian and Italian Freud blades, both are middling quality and quality control on the Italian blades has taken a nosedive in recent years.* Rip blades require less power so I would go flat top, full kerf. *Thin kerf on combo & crosscut. Probably doesn't matter on a GP.



What is your reasoning for this statement and do you have any demonstrable proof that power requirements are less for ripping than crosscutting?

I've been sawing for about 50+ years and it's always been my experience that ripping requires more power. I have bogged down many a table saw or circular saw ripping with the grain down the length of a board. Rarely does this happen when crosscutting. The entire theory behind "thin kerf" blades is to reduce the amount of fibers which are cut and carried away by the gullets. A crosscut blade does not have sufficient gullet depth because there are 2 or 3 times the number of teeth and there is no room left for larger gullets.

Circular saws may have been the inspiration for thin kerf blades, especially the smaller battery powered ones, I donno? All my battery saw came with the thinnest blades possible, about 1/16" kerf width.

Like a lot of woodworkers, I started out using full kerf blades on my Craftsman contractor saw years ago, because those were all that was available. Today there almost too many choice for a beginner to select from and it can get confusing. Here's a video that will help explain the differences:







Also a good link:
https://www.woodcraft.com/blog_entries/choosing-the-right-table-saw-blades


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## Woodknack (May 12, 2017)

What I mean is a rip blade will require less power when ripping than a gp, combo, or crosscut blade will require for ripping. So you can go full kerf with ftg on a rip blade because that blade allows you to make smooth bottom grooves, box joints, etc. It's more versatile than a thin kerf rip blade. If you have 3 HP or bigger saw then you'll never notice the difference between thin and full kerf, or gp vs rip blade; but since the op has sub-2hp then it may make a difference.


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## firehawkmph (Apr 26, 2008)

using the right blade for the right situation makes a big difference. Combo blades are a compromise, don't expect them to do everything perfect. I've tried just about every blade over the last 40 years, and I've settled on Forrest blades for my shop. I have four different blades and use them for what each is intended for. I keep a few cheap blades around for cutting 2 x 4's. Here's a video from the Forrest rep, he explains the different blades and also some good tips for each type of cut. I've met him several times ATM our local woodcraft store and watched him do this live. Good guy, knows his stuff.
Mike Hawkins


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## TimPa (Jan 27, 2010)

where is knotscott (sp?)? he always had great blade info when this subject came up.


you can do a search on blade selection as this comes up almost every month here.


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## hawkeye10 (Feb 18, 2015)

firehawkmph said:


> using the right blade for the right situation makes a big difference. Combo blades are a compromise, don't expect them to do everything perfect. I've tried just about every blade over the last 40 years, and I've settled on Forrest blades for my shop. I have four different blades and use them for what each is intended for. I keep a few cheap blades around for cutting 2 x 4's. Here's a video from the Forrest rep, he explains the different blades and also some good tips for each type of cut. I've met him several times ATM our local woodcraft store and watched him do this live. Good guy, knows his stuff.
> Mike Hawkins
> 
> https://youtu.be/-SgdTXphEJ4



Great video Mike. According to him, I have been adjusting the height of my blade all wrong.


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## Tool Agnostic (Aug 13, 2017)

firehawkmph said:


> using the right blade for the right situation makes a big difference. Combo blades are a compromise, don't expect them to do everything perfect. I've tried just about every blade over the last 40 years, and I've settled on Forrest blades for my shop. I have four different blades and use them for what each is intended for. I keep a few cheap blades around for cutting 2 x 4's. Here's a video from the Forrest rep, he explains the different blades and also some good tips for each type of cut. I've met him several times ATM our local woodcraft store and watched him do this live. Good guy, knows his stuff.
> Mike Hawkins
> 
> https://youtu.be/-SgdTXphEJ4


Thanks for sharing this, especially the YouTube link. The most valuable lesson I got from the video applied to different cuts on a table saw:

* Rip Cut: Raise the blade high. The carbide stays cooler and expands less during the cut.

* Crosscut Solid Wood: Raise the blade one inch above the top of the wood.

* Plywood: Set the blade height so that the bottom of the gullet is at the height of the plywood, to reduce or eliminate tearout. Cutting plywood is hard on blades and dulls them faster. If you have a Woodworker II blade, try to limit the amount of plywood that you cut or buy one of their plywood blades.

Before this morning, I always lowered the table saw blade to align the bottom of the gullet with the top of the wood to be cut. 

I had not considered heat issues when cutting before, especially regarding rip cuts. Carbide tips expand as they heat up from friction during the cut. As they expand, the kerf expands too. Furthermore, the expanding carbide tips can squeeze the wood between the blade and the fence. None of that is good. By raising the blade high, you reduce the amount of time that that carbide tips are in contact with the wood. Doing that reduces overall friction, which significantly reduces the temperature of the blade and the carbide tips. Lower temperatures means that the carbide tips expand less during the cut.

In case anyone cares, I have two Forrest blades: 

* A standard kerf Woodworker II, which I just sent back to Forrest for sharpening. It has performed well, although I don't like the ATB tooth pattern for box joints. It is incredibly sharp and clean cutting.

* A thin kerf Woodworker II, but with the #6 grind, which includes a raker tooth to make more of a flat bottom. (The ATB "ears" for scoring are still there.) I bought it to use when the blade above is out for sharpening. 

I am not sure how well the thin kerf blade will do for box joints. The "fingers" would be very thin. I am using it for general rip cuts and crosscuts until the blade above comes back. Forrest tech support told me that it is good as a general purpose blade. Furthermore, the tech support person at Forrest told me that the raker teeth will make rip cuts better and easier - cutting faster and requiring less force. I wondered why most people don't buy that #6 grind version of the basic Woodworker II for general use. The tech support person seemed to agree, and he added the part about easier rip cuts. He convinced me that the #6 grind blade with the raker teeth would be as good or better than the standard ATB

I am very pleased with my Forrest blades. They really do leave "glue ready" surfaces after the cuts. I use cheap blades for non-precision work, like cutting up scrap. I have a Freud SD208 dado set, which is okay but not great. I wish I had bought the Oshlun dado set, which is superior in several ways and is in a similar price range.


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## NoThankyou (Mar 21, 2018)

*Blasphemy?*

OK,
Allow me some blasphemy here. 

It really doesn't matter which type of blade that you use, just be consistent. Consistency will give you a lot less table saw alignment aggravation.

Right Tilting Saws
If you have aligned the riving knife on your saw with a full kerf blade, the riving knife will pull the wood away from the fence when cutting with a narrow kerf blade. If the riving knife is aligned using a narrow kerf blade, the wood will be pinched against the fence making for a tough cut.

Left Tilting Saws
Switching between full kerf and narrow kerf blades will invalidate the ruler setting on your fence. 

All Saws
Finally, most riving knives are designed for full kerf blades. Pushing wood with a 3/32 kerf through a 1/8 kerf designed riving knife is a chore. On my UniSaw I've thinned the riving knife for use with thin kerf blades.

I have never subscribed to the theory of less power needed with a thin kerf blade. Just feed slower and pay more attention to the feed back from the saw.

IMNSHO - Riving knives must be aligned with the arbor flange and not the saw blade. But that is for a discussion over some flavored ice cubes and a more relaxed atmosphere.


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## woodnthings (Jan 24, 2009)

*riving knives VS splitters*

I will hazard a guess that any table saws with less than 2 HP motors, like a 10" hybrid saw, will have a riving knife that will accommodate a thin kerf blade. My own Craftsman 22124 10" hybrid certainly does. My older 1980's 12" motorized Craftsman table saws have splitters that accommodate think kerf blades as well. My 12" 5 HP Powermatic has a 1" arbor and I only use full kerf blades.

The entire reason for having thin kerf blades for saws with less than 2 HP, is that they require less power because they remove less material, that just the fact. 

The right tilt VS left tilt argument has been going on for years and there is no resolution, just preference. In fact, you will have a difficult time finding a new 10" or 12" table saw that tilts right these days:
http://www.grizzly.com/products/10-3HP-220V-Cabinet-Table-Saw-with-Riving-Knife/G0690
I have made the point here that most folks are right handed and that drives the preference for a left tilt saw because the work is push forward with the right hand and it's easier to control and keep it registered against the fence.

I have also advocated for the use of splitters when possible because they do 2 different things that increase table saw safety:
The first is to keep the kerf open after the cut is partially made which prevents the wood from closing on the rear of the spinning blade and being propelled over the top, and back at the operator.
The second thing is that they keep the workpiece registered against the fence at the rear and prevent it from rotating off, and coming over the top of the spinning blade at the rear and back at the operator.
Neither of those do anything to prevent one from cutting their hands or fingers off, which is what the blade cover is intended to do.

Of course there are certain operations where a splitter will not work, a partial depth cut or stopped kerf. :smile2:


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