I've been using Freud 24 T thin blades for ripping 8/4 white oak and have not seen any deflection.
I'm wondering if those who do see deflection and/or vibration have a saw with a slight arbor defect.

 

Gene, you beat my post by a few seconds.

Your theory does sound plausible, although I think that most saws these days have essentially perfect arbors.

More than anything, I find that it will be a stubborn knot that starts the trouble with these blades. But for everyday typical cabinetmaking use, the thin blades work well.

 

There's two sides to that argument.

Firstly, the blade removes less wood than the thicker blade, which makes it easier to push wood through your saw.

The flip side is that if you are cutting difficult wood, the blade will tend to heat up more, which in turn causes the edge of the blade to expand slightly. This is what gives the blade that characteristic wobble.

I find that if you make sure the blade is kept sharp and you don't push it too hard, that the blade will stay flat and do an excellent job. Don't be tempted to run the blade once you notice that it is starting to dull and you should be fine.

 

I used a thin rim Freud ripping blade for several years and the cut is not as smooth with them as with the glue line Freud I use now and that's on a unisaw so the arbor is good. I did find that using saw blade stabilizers improved the cut when I needed it and the stabilizers definitely improved chop saw cuts at 45* on hard woods.

 

Yep. Never use one without stabilizers.

 

Don, when I hear about blade deflection the first thing that comes to mind is "Don't force it, let the tool make the cut." This is also true for other types of saw blades and router bits. You need to move just fast enough to prevent burning with a smooth and steady feed rate. This will give you the cleanest cut possible.

Vibration occurs when a tool is out of true. If you are getting vibration stop using the tool and find out why. A bent saw blade or router bit shank could be the cause; the cutter may not be properly tightened. Safety first!

I am currently using a Forrest Woodworker II thin kerf blade and have had no problems with it; the cuts are first rate. Forrest recommends using a stiffener with all table saw blades to improve the cut. I used the Forrest stiffener with a Guhdo-Gmaxx standard kerf blade and I believe the cut was smoother.

 

Don, when I hear about blade deflection the first thing that comes to mind is "Don't force it, let the tool make the cut." This is also true for other types of saw blades and router bits. You need to move just fast enough to prevent burning with a smooth and steady feed rate. This will give you the cleanest cut possible.

I am currently using a Forrest Woodworker II thin kerf blade and have had no problems with it; the cuts are first rate.

Absolutely! I have a pair of Woodworker II thin kerf blades, 3/32" thick. Wonderful performance. One's in the saw, and the other is either being sharpened by the factory, or waiting in the cabinet for when I need to replace the dull blade in the saw.

8/4 hardwoods require a slow feed rate, and knots in Hard Maple do drive me a bit crazy ... but I think that's the underpowered table saw, not the blade. I recommend the Woodworker II, and Forrest's factory sharpening service, without reservation.

 

That is a new brand of blades for me.

 

I've used both but prefer the cut of the normal kerf blades. Though, I have a 3HP TS so don't have to worry much about bogging down.. I would use thin kerf if I was cutting a lot of thin pieces as it would yield 20% more (or take less wood to get the same amount).

If you are experiencing vibration, try a set of stabilizers.

 

if you are cutting difficult wood, the blade will tend to heat up more

I must respectfully disagree. I've seen the comment made more than once that thin kerf blades will build up more heat, since they have less thermal mass. I have not seen any documentation to support that idea, and as a [retired] scientist, it makes no sense to me.

The amount of work required- and the amount of heat generated- is proportional to the amount of wood required; a blade with, say, half the kerf width will use half the power, and create half the heat of a full kerf blade. So, even if the mass of the thin blade is less (by half), the heat build up (temperature) will be the same in the two blades. In fact, since the total surface area of the two blades is virtually identical, with less mass- and less heat- the thin blade will theoretically dissipate heat faster than the thicker blade.

I'll get off my soapbox now! :wink:

 

John you make some points and they make since.

 

Make sure you check the alignment on the saw, blade to table and fence to miter slot. If the alignment is off it will cause some deflection of the blade when you are forcing the material to follow a line that is not straight.

 

thin kerf blades

I have looked into thin kerf blades for the TS. The thinnest I have found is made by Total Saw Solutions : saw blades and other tooling for the woodworking, metal and plastics industries which they say is as thin as a dime (1/16"). I don't have one, but thought of getting one for cutting slots for splines. Thought of it, but haven't done it yet. Right now I am using a Forrest Woodworker II with a 1/8" wide kerf. It makes a flat bottom cut which is needed for the spline slots that I make. I think it does a wonderful job. Much better that the Freud blade that I had been using. Malcolm / Kentucky USA

 

I have looked into thin kerf blades for the TS. The thinnest I have found is made by Total Saw Solutions : saw blades and other tooling for the woodworking, metal and plastics industries which they say is as thin as a dime (1/16"). I don't have one, but thought of getting one for cutting slots for splines. Thought of it, but haven't done it yet. Right now I am using a Forrest Woodworker II with a 1/8" wide kerf. It makes a flat bottom cut which is needed for the spline slots that I make. I think it does a wonderful job. Much better that the Freud blade that I had been using. Malcolm / Kentucky USA

Dedicated to kerfing, I'd think you'd be golden! But with a hefty pricetag. As long as you have a matching arbor size, you can get away with much smaller diameter and much cheaper blades. I can see where 1/16th splines sure would make for some very attractive boxes. Working on a 60 x 18 shadow box made out of Zebra wood. Set it off with Ebony splines, made all the difference in the world.

 

I took a quick look at those Tool Saw Solutions blades. One thing that I did not see was any description of the tooth profiles (ATB, or what?) For the cleanest spline cut, you'd probably want a profile that cuts a flat bottom (like most rip blades do).

You could save a lot of money and get a 1/16" kerf by putting a 7-1/4" thin kerf circular saw blade on your table saw. You don't need a very deep cut for splines, so the smaller blade diameter shouldn't be a problem. [However, if might be hard to find a flat bottom cut blade with those, as well].

 

BobJ3 used to like to point out that just because you have a 10" saw doesn't mean you have to use a 10" blade.

 

What does happen is that the thinner blade, having less mass as you quite properly point out, will heat up much faster. However, I don't believe that it is only half the mass of a thicker blade in the case mentioned by the OP.

What I don't understand is how a thinner blade will get rid of the heat any faster while it is being used. Surely, it will continue to heat up, will it not?

Sorry, I have to jump back onto my soapbox!

First of all, my saying that the thinner blade was half the mass was only as an example- hoping that it would make the concept easier to understand. I fully realize that thin kerf blades aren't half the width of regular blades.

Let's use instead real examples. I have a "stock" Craftsman blade, with a 0.125" kerf, and mass of 790 g. My general purpose Oshlun thin blade has a 0.098" kerf and 628 g mass. The mass of the stock (full kerf) blade is 1.26 times that of the thin blade.

It is true that a thinner (i.e. lower mass) blade will get hotter, if the amount of heat added is to the blade is the same. My point is that the full kerf blade creates more heat, since it removes more wood in a pass. In fact, the regular blade needs 1.28 times the energy- and creates 1.28 times the heat- than the thin blade (0.125"/0.098" = 1.28).

So, the less mass of the thin kerf blade is offset by the lower amount of heat it generates in making a cut, and the temperature increase is about the same as with a regular blade. Actually, the body of my thin kerf blade is somewhat "meatier" (more mass), relative to it's kerf, than my stock blade, so it's temperature rise would actually be less.

My comment that thin blades are better at losing heat is based on the concept that surface area plays a huge role in heat dispersion (cooling). The greater the surface area, the more easily heat is lost (why a radiator with lots of surface area is more efficient than a solid cube of the same mass).

My point was that both blades have nearly the same total surface area [two sides of the body, plus exposed edges (gullets)]: ~129 sq in for the thin, ~131 sq in for the stock blade, from my measurements. So, with a larger SA to mass ratio, the thin blade will dissipate heat more efficiently. At the same time that it's cutting wood, the blade is also spinning in air outside the cut, and dissipating heat. So, the temperature increase is a function of the net heat gained (heat produced from cutting minus that lost from dissipation), and the thin blade should get any hotter than the stock blade.

This assumes the same cutting speed. It occurs to me that since a thin blade needs less power, there might be the tendency to push the wood through the blade faster, since it isn't bogging down. In that case, the thin blade will heat up more.

FWIW, I tried a quick experiment. I don't have a lot of hardwood that I wanted to sacrifice in the name of science, but I ripped about 4' of PT 4x4 with my thin blade at ful extension, feeding at a rate that produced a slight bogging down. With a surface reading thermometer I couldn't detect any temperature change before and after. I don't have the time, nor do I want to push my equipment to cut hundreds of feet, or risk burning out my motor to do a full comparison to reinforce scientific first principles.

Off the box!

 

The heat issue is only one aspect. The other most important issue is grain direction and change of direction. The reason I said that using stabilizers made such a difference if making chop saw cuts at 45* in hardwood is because the changes in grain between early and late wood cased the blade to deflect back and forth as it passed through harder and softer alternative layers. I bought what I thought was a good dedicated chop saw blade and got horrible results in red oak until I added stabilizers which effectively stiffened the saw plate enough to resist the torsion forces of the changing grain. The same holds true in ripping, although to a lesser extent since you are mostly following the grain. The stiffer the saw plate the better the blade is able to resist these torsional forces.

 

One of, if not the most, prolific contributor, Bobj3 posted so many posts showing how he would pass on his great knowledge to the forum.

Are his posts still able to be found showing so many of his jigs?

 

@jw2170 unfortunately the new forum format makes it harder because they removed the "view uploads" button, but I have been able to find some posts by using his name and the word jig in the search box. Unfortunately with him having so many posts it's a lot to search thru