Can't figure out why table saw is burning wood


estesbubba

Recommended Posts

I trying to track down why I'm getting burning while ripping longer boards. I've tried several different things with no luck so far. I'm using a Frued Premier Fusion full-kerf blade which feels really sharp. I've had it for a couple of years with limited use on my Steel City cabinet saw since I haven't done a lot of projects plus use other blades. I've tried it with my fence parallel to my blade and .002" away front to back. My splitter aligns to the left side of the blade (how it came from factory) which leaves it little gap on the right side of the blade. 

 

I cleaned the blade really well yesterday using CMT 2000 and then sprayed it with PTFE lubricant which I've done for years. I put the blade in the saw and made just 2 rips with it and the wood is burning on both sides and the teeth already have build up on them. Since it's burning on both sides I don't think it's fence alignment. 

 

Any ideas on what is going on or to try next? Should I move the splitter to align with the right edge of the blade even though all blades aren't the same width? I have all full-kerf blades but they still vary a little.

 

IMG_0488.JPG

 

IMG_0489.JPG

Link to comment
Share on other sites

how good is your factory splitter?  If it is kinda crappy, I would honestly suggest dropping the $40 on an MJ Splitter Steel Pro.  Ever since I installed that on my saw, I have not burned a single cut (and that was coming from burning every cut before).  It is worth the extra $15 to go with the SteelPRO.  Ohh and you will have to get/make a new ZCI.  

Link to comment
Share on other sites

==> burning on both sides and the teeth already have build up on them
Based on your description, I think PB’s spot-on… You’ve probably got wonky stock… If so, I’d rip it on the bandsaw…

 

But back to the issue at hand: assuming good technique, PB’s got the right idea… Let me add a qualifier on his advice – removing the splitter will tell you if the stock is closing, but you’ll pinch the blade for sure if that’s the case… If you’ve never managed pinched blade/stock, you need to watch for kickback or stalling the saw… I’m not sure what saw you’ve got, but if it’s high-HP, the stock might shatter and kickback in pieces…

 

Do you have any other stock to try?

 

Have you re-verified your alignment, or relying on an old alignment/setup effort… If you suspect alignment, you need to re-verify, not rely on what it was last month – things change…

 

==>My splitter aligns to the left side of the blade
I’m not so sure that’s a good thing – mine have always been centered in the kerf… If you’re using 0.125 kerf blades, usually a splitter is 0.10 and allows space on each side of the kerf…

 

==>then sprayed it with PTFE lubricant which I've done for years

Not necessary.

 

 

==>I have just resigned myself to the fact that cherry burns

??? - I go through several thousand bf Cherry per year... If it burn's, I've got a problem with alighment, the blade or my technique...

 

 

==>That looks like a 50t blade, a 30t blade with deeper gullets might be better

Looks like the standard Freud ATB... Not exactly the best ripping blade... Their dedicated ripper would be a better choice... But the ATB should work without burning...

Link to comment
Share on other sites

Those are some long boards.  I have just resigned myself to the fact that cherry burns.   That looks like a 50t blade, a 30t blade with deeper gullets might be better.  

 

 

A 40 tooth combo blade will cut just fine for 95% of what you throw at it. Cherry should not burn any more than any other hardwood.

Link to comment
Share on other sites

I would drop down to a 24t blade that helps to reduce burning with rip cuts. I tend to increase my feed rate with woods that are burning.

 

My splitter is directly in alignment behind the blade.  

 

If your noticing a lot of sawdust coming off the back of the blade and onto the table. Your fence is not in alignment with the blade.

 

-Ace-

Link to comment
Share on other sites

To clarify the blade is 40 tooth Hi-ATB and wood is 3/4" walnut. I checked fence alignment last week and it does lock down tight. I've checked the arbor and there is no runout. I have a 3HP SawStop and using the stock splitter and riving knife and believe they are 0.90" thick. 
 
It could just be that wood is binding. I haven't had any issues with plywood using the fence and the edges are glass smooth. I've mainly used the saw for my outfeed table and three sleds so more sheet goods than hardwoods. I did notice on that walnut rip that is was harder to push than it should have been. 
 
The manual says to align the splitter with the left of the blade but maybe I'll try centering it. 
Link to comment
Share on other sites

 

To clarify the blade is 40 tooth Hi-ATB and wood is 3/4" walnut. I checked fence alignment last week and it does lock down tight. I've checked the arbor and there is no runout. I have a 3HP SawStop and using the stock splitter and riving knife and believe they are 0.90" thick. 
 
It could just be that wood is binding. I haven't had any issues with plywood using the fence and the edges are glass smooth. I've mainly used the saw for my outfeed table and three sleds so more sheet goods than hardwoods. I did notice on that walnut rip that is was harder to push than it should have been. 
 
The manual says to align the splitter with the left of the blade but maybe I'll try centering it. 

 

 

Its not .90" thick :) Its more likely the board is not flat or straight. If your getting good rips on plywood I wouldn't be to worried about it. Just pay more attention to the HW boards. Make sure you keep the wood tight against the fence, watch the very end of the fence.

Link to comment
Share on other sites

==>99% of the time the wood will tell you why its burning

+1, make that +2...

 

==>Cherry should not burn any more than any other hardwood.
Well, some species have a little more pitch, et al… But to the point at hand: where there’s burning, there’s an issue…

 

==>The manual says to align the splitter with the left of the blade
Interesting… I can think of many reasons not to do that, and darn few as to why you would… The more I think about it, I'm really not sure why you would align the splitter to the left side... I don't like recommending against the manual, but I'm not sure that's good advice...

 

==>board is not flat or straight
99% that’s the case…

 

==>believe they are 0.90" thick.

Maybe 0.09”?

 

==>using the fence and the edges are glass smooth
Then it’s the Walnut… A surface planer is your friend… :)

Link to comment
Share on other sites

I think you have it figured out.

 

My bet it's the splitter, just get that behind the blade and see. Another thing you mentioned is the wood being hard to push. That could also be from tension in the wood. Does the off cut line up with the board or is it curled in/out? 

 

Last, if everything seems to be correct with your set-up. Try the more aggressive 24t blade.

 

-Ace- 

Link to comment
Share on other sites

Some wood just burns very easily....cherry is certainly one of them.  You might try raising the blade a little to see if it helps.  Be sure your feed rate isn't too slow.

 

It's really hard to evaluate a blade's sharpness by feel....the pointier the tips, the sharper the blade will "feel" to your fingers, but it's not indicative of the face of the teeth.  If you have one, I'd try a different blade to eliminate that as a variable.     

  

The Freud Fusion is more prone to burning than some blades too....it has very tight side clearances, as well as a dual side grind....the same characteristics that help it give a shiny polished edge also make it more prone to burning.

Link to comment
Share on other sites

Thanks for all the tips. I also called SawStop and the guy said that everyone has a different preference on where to align the splitter - left, center, or right. Since he uses all full-kerf blades he said he likes align the splitter with the right side of the carbide. He said if you use both thin and full-kerf blades then the left side is safer. So I think the first thing I'll try is either center or right.
 
Knottscott is also on that the Freud Fusion will leave a glass edge which I frequently can get with the blade. Sounds like because of this it is also pickier which maybe I'm just running into more with this saw. The blade could be dulling but I don't see any reflections on the edges. 
 
Oh, and I had my decimal off by a digit - I meant .090" thick :)
 
I have some rift saw red oak which I'll use for my test cuts which should be pretty stable when cutting. 
Link to comment
Share on other sites

 

Thanks for all the tips. I also called SawStop and the guy said that everyone has a different preference on where to align the splitter - left, center, or right. Since he uses all full-kerf blades he said he likes align the splitter with the right side of the carbide. He said if you use both thin and full-kerf blades then the left side is safer. So I think the first thing I'll try is either center or right.
 
 

 

That is not right. The splitter/riving knife should be aligned with the highest point on the carbide to the right closest to the fence. This allows you to error to the open rather than closed toe of the fence. If your fence open by .02 and your aligned to the left The splitter will keep the material away from the fence by .02. The clearance side should be on the off cut so that the work piece can be held tight against the fence and there is a small allowance for movement of the narrow off cut. In short you have to slightly tweek the riving knife to keep the wood against the fence. As you keep pressure it burns the off cut when you change hand position the workpiece moves away from the fence since the riving knife springs back. This essentially gives you an alternating burn pattern. 

If you want to run a thin kerf buy a thin kerf riving knife.

Link to comment
Share on other sites

That is not right. The splitter/riving knife should be aligned with the highest point on the carbide to the right closest to the fence. This allows you to error to the open rather than closed toe of the fence. If your fence open by .02 and your aligned to the left The splitter will keep the material away from the fence by .02. The clearance side should be on the off cut so that the work piece can be held tight against the fence and there is a small allowance for movement of the narrow off cut. In short you have to slightly tweek the riving knife to keep the wood against the fence. As you keep pressure it burns the off cut when you change hand position the workpiece moves away from the fence since the riving knife springs back. This essentially gives you an alternating burn pattern. 

If you want to run a thin kerf buy a thin kerf riving knife.

 

I guess what difference does it make. I never go to final width on a huge rip cut. So if ya get a little wavy or saw mark's or burning. The splitter really prevents the wood from running up the back of the blade causing kick-back. Or say wood has tension during the cut, the wood closes on the back of the blade.

 

After I make a rip cut I'm probably 1/4 to 1/8 away from my line anyway. Then I move the fence and re-run the cut, skimming the blade to clean up my cut, getting on my line. Get's rid of any burning, etc. 

 

-Ace-

Link to comment
Share on other sites

I guess what difference does it make. I never go to final width on a huge rip cut. So if ya get a little wavy or saw mark's or burning. The splitter really prevents the wood from running up the back of the blade causing kick-back. Or say wood has tension during the cut, the wood closes on the back of the blade.

 

After I make a rip cut I'm probably 1/4 to 1/8 away from my line anyway. Then I move the fence and re-run the cut, skimming the blade to clean up my cut, getting on my line. Get's rid of any burning, etc. 

 

-Ace-

 

In this case if the fence error is out and the splitter is left all your plywood panels will be out of square by the amount of the fence error. If you don't use plywood then no big deal. But then why use the tablesaw anyways if you know you will have to clean up the cut. Why not use the safer and faster tool for the job the which is bandsaw. No matter how you slice it its always going to be best to just adjust the saw properly and move on to making sawdust.

Link to comment
Share on other sites

==>called SawStop and the guy said that everyone has a different preference on where to align the splitter - left, center, or right. Since he uses all full-kerf blades he said he likes align the splitter with the right side of the carbide. He said if you use both thin and full-kerf blades then the left side is safer

 

I don’t like to counter what the mfg says, but I really don't buy into that advice… I can see the align-right argument and I use kerf-center, but align-left seems very dubious… As PB noted, if you use thin kerf blades, get a thin kerf splitter…

 

 

==>the blade is 40 tooth Hi-ATB and wood is 3/4" walnut
Hi-A/T is really not the right grind for ripping hardwoods… Good for sheet goods, but not ripping hardwoods…

 

On the several posts referring to burning: Some species are more prone to burning than others… That point accepted, you should still not see burning on a regular basis unless something is wrong… In the last several years, I’ve seen burning unrelated to a dull blade only once – and that was due to improper fence alignment… If you see burning check alignment, edge sharpness, incorrect grind, technique, underpowered saw, wonky wood, etc… It’s an important point, so I’ll say it again: burning is not ‘normal’ or inevitable… If you see regular burning, start investigating… When I see burning, it's time to send the blade for sharpening...

Link to comment
Share on other sites

Just looked at the specs on my riving knife and spreader:

Thickness: 2.3mm

Blade body range: 1.8-2.1mm

Kerf range: 2.35-3.5mm

The blade body on the Freud Premier Fusion is 2.6mm and almost as wide as the carbide. Could be this blade is a bad match with this saw. Maybe not. Could be a dull blade or bad splitter alignment. I got my first two saws tuned in and will get this one.

On the last cut the cutoff bowed into the board so probably contributed to burning.

post-8178-142474338549_thumb.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Who's Online   2 Members, 0 Anonymous, 56 Guests (See full list)

  • Forum Statistics

    31.2k
    Total Topics
    421.8k
    Total Posts
  • Member Statistics

    23,757
    Total Members
    3,644
    Most Online
    R Parekh
    Newest Member
    R Parekh
    Joined