Replies

1. 
   THintz | Oct 05, 2007 09:46am | #1

   Unfortunately, here are a number of reasons a blade can burn wood. It can just be dirty. A buildup of pitch and such, sometimes not even readily visible causes heat and provides a substance to "burn" onto the wood. Clean the blade even if it looks clean, just in case.

   A dull blade will feel sharp to your finger but can easily burn the wood.

   Miss alignments between the fence and blade can force the side of the blade to rub on the edge of the wood and result in burning also.

   Moving the wood too slowly can do it but if all of the above are eliminated, feed rate errors get harder to do. I have developed a feed rate that gives me the feel that the blade is engaged with the wood and the teeth are cutting without being overloaded. Nothing scientific, just a feel I came to be comfortable with that my saws seem comfortable with also.

   Tom Hintz

   Because there is always more to learn!

2. 
   Lataxe | Oct 05, 2007 12:45pm | #2

   Mr 880,

   If you could give a few more details, diagnosis would be easier. For instance:

   *  Is all wood burnt or just some species?

   * Does it burn thin as well as thicker sections?

   * What size and # of teeth on the blade; what type of teeth (profile, rake)?

   * Is the wood burnt on both sides of the blade or just one?

   * What is the degree of burning - just a bit of "dark" or smoking and screeching?

   * Is the wood nipping together after it is cut?

   * Any other symptoms and conditions you can think of.

   It could be wrong blade, just the particular wood, misaligned fence, wrong feed rate, wobble in the blade, etc..  The symptom details will help to eliminate some of these possibe causes.

   Lataxe

3. 
   Samson | Oct 05, 2007 06:51pm | #3

   In my experience it most often happens for the same reason a router bit sometimes burns wood - hestitations in the feeding of the wood into the blade (or with a handheld router - hestitations in moving the tool).  For ample, if you stop to reach for a push stick and leave the blade spinning on one spot - or otherwise don't smoothly move the wood through the cutting zone, you invite burning from all that friction.  Cherry is particularly susceptible, but maple too especially when thick (like 8/4).

4. 
   Knotscott | Oct 05, 2007 10:05pm | #4

   Tom pointed out alot of possibilities.

   Do you use a jointer and planer prior to sawing? If the wood is not flat and straight, it'll also be more prone to burning.

1. 
   Woodman880 | Oct 05, 2007 11:40pm | #5

   I think I fixed my table saw wood burning problem by re-aligning the fence. Rookie mistake.

1. 
   THintz | Oct 06, 2007 10:44am | #6

   Good deal on fixing it!

   By the way, you don't have to be a rookie to make that mistake.... Now. remember to check that alignment occasioanly and you will be ahead of lots of veterans!Tom Hintz

   Because there is always more to learn!

5. 
   kesac | Oct 07, 2007 02:56am | #7

   Pitch build up.  Ripping with combo blade. Pitch build up.  Cutting cherry. Pitch build up.

6. 
   WillGeorge | Oct 08, 2007 07:28pm | #8

   First off I want to say that I do NOT disagree with the statements of the other posters.

   However, I have noticed over the years burning on some sticks (I usually use some pretty hard woods) and I KNEW my blade and fence and whatever was 'spot on'. As in the next stick cut without any burning.

   When cutting the 'sticks' some will bow/twist slightly as they are cut and push against the blade. Nothing you can do about it that I know of. If you lay the stick against the fence you can 'see' that after the cut the stick no longer contacts the fence along its full length. I call it reaction wood. Sometimes I call it much worse things!

   If I am using really expensive woods I will rip a bit oversized so I can trim off the burn.

   Just what I do. Does not make it right!

   
   

   ---

   Edited 10/8/2007 12:29 pm by WillGeorge

1. 
   Woodman880 | Oct 08, 2007 08:00pm | #9

   What you say makes a lot of sense. Sometimes I don’t think you can avoid burning wood. As for cutting things over-sized, after some expensive mistakes, recently I’ve started cutting a lot of things over-sized. I’ve learned the hard and expensive way that you can always take off a little more but you can’t add that 1/4 of an inch mistake.

7. 
   dbridge | Sep 14, 2020 08:45pm | #10

   Help. I have a new table saw, a new blade. Today the saw was burning the wood. I had a diablo 80T blade on plywood. I cleaned the pitch after I stopped the cut and tried again. Same thing. I changed it back to the general use blade and cut a piece of scrap and the same thing happened. I am new to woodworking. I don't know what happened or what to adjust. I did not have this problem when I used it on a piece of MDF 2 weeks ago. Any suggestions would be most helpful.

8. 
   DRBWWing | Sep 15, 2020 10:35am | #11

   Friction causes heat.

   Wood burns in the presence of heat.

   Resin is an accelerant.

9. 
   lat_axe | Sep 16, 2020 06:54am | #12

   Dbridge,

   There are quite a few possible causes of too much friction between wood and blade that causes burning. Can you say:

   What table saw are you using and has it been set up properly?

   How thick is the plywood?

   Are you making a rip-style cut (along the fence) or a cross-cut type cut (with a sliding carriage or mitre gauge)?

   Common causes of burning are:

   Too many teeth in hard and/or thick and/or gummy and/or sugary timber.

   Blade and rip fence out of alignment or mitre gauge slot not aligned with the blade.

   Arbor or blade wobble

   Too slow a feed speed of wood into blade (often related to the first cause)

   There are other causes of burning but a diagnosis needs more information from you about the details of your problematic cut.

   Lataxe