Bad burning on table saw cuts

[Brad Tallis]

Hello All-

I am experiencing bad burning on oak while cutting on my tablesaw. I am using an Incra TIII fence and a Freud all-purpose blade.

In the pictures below, you can see that the side between the blade and the fence is burning real bad, but the side on the other side of the blade is coming out clean as a whistle.

My assumption is that my fence must be "pinching" the wood toward the blade, which is causing friction. And the reason the outside piece is fine is because it isn't piched against the fence. Is this correct? Or could it be that my blade isn't perpendicular with the table? I checked it with a square, but is is one of those cheapy $5.00 plastic squares, so I don't hold much confidence in it.

Any ideas here?

Thanks.

Brad

http://home.comcast.net/%7Estarjumper/images/cut01.jpg

http://home.comcast.net/%7Estarjumper/images/cut02.jpg

PS. Oh, ya. A tool gloat... I just got a Milwaukee 5625 3-1/2 HP router. It's the one with the built-in router lift. I've used it to make a few raised panels already and I love it! It's kind of an odd picture as I have it mounted upside down next to my tablesaw, but I knew I would need a picture for the Tool Gloat Picture Police. :)

http://home.comcast.net/%7Estarjumper/images/router01.jpg

[Tyler Howell]

Sounds Like the correct diagnosis. DAMHIKT.
Spend some quality time and tune her up, starting with the blade to miter track.
The pros can do it with a square and chunk of wood.
I had to resort to some of this stuff.
http://www.ts-aligner.com/videos.htm (http://www.ts-aligner.com/videos.htm)
PS good Gloat.:cool:

[Vaughn McMillan]

Brad, I'd check to be sure the fence is aligned parallel to the blade. I think your assumption about pinching is correct, and I'm guessing the square you used to check things wasn't within the few thousandths of an inch that your fence needs to be. There have been several good discussions here on SMC about gauges for adjusting fences and blades.

HTH -

- Vaughn

[Don Selke]

Hi Brad:
You may want to check out www.Newwoodworker.com (http://www.Newwoodworker.com) and click on Tips and Tricks, Table Saw Dial indicator, Table Saw allignment. The site shows you how to build a dial indicator jig and how to use it. John is a member of Saw Mill Creek.
You may also want to use a 28 tooth rip blade as well, oak requires a aggressive blade when ripping.

[Steve Schoene]

Probably is fence not parallel to blade, but if so, what could have happened to move it out of alignment, since I assume you haven't had burning on all rip cuts.

You may also have some movement of the oak as it is cut. I notice you didn't have a splitter in view, install the splitter and see if that has an impact on the quality of the cut.

[Alan Turner]

You might also want to check to see that the blade is clean. Dirty teeth will burn your work every time. Also, a rip blade will give you a lot less burning, although I rarely use one. I typically run a 40 tooth, alternate bevel ground, such as a WWII Forrest, or Leitz, and I use it for both rips and crosscuts, except on finished ply, which I don't run often anyway.

[Al Navas]

I ran into the exact same problem when ripping white oak, and must agree with Alan: My blade was not clean. I immediately switched blades (to a brand-new / clean one), and the burning went away immediately - on the same board.

I believe that in your case it would be worthwhile to check alignment, etc.


Al

[Per Swenson]

Brad,

I have a incra fence and set it up with a feeler guage.

See here. http://www.sawmillcreek.org/showthread.php?t=29246&highlight=feeler+guage

Clean saw blade is also a must.

I use, Simple Green.

Hope this helps.

Per

[Rob Blaustein]

I checked it with a square, but is is one of those cheapy $5.00 plastic squares, so I don't hold much confidence in it.


Brad,
Others have already offered any suggestions I might have made but I'll comment on the plastic triangles. I can't recall the brand I have but I got it at an artist supply place (less than $10 I think) and they are generally felt to be very accurate. I can't give you numbers here, but I've lined it up with other squares I have (e.g. a Starrett combo square) and it seems to be spot on. Also, many of the table saw gurus like Jim Tolpin and Kelly Mehler use them for TS setup.
Rob

[Howard Acheson]

There are two issues. The first is that the fence may not be parallel to the miter gauge. Here is something to set that correctly:

Here is the low tech, low cost way to align a tablesaw that I learned maybe forty years ago and teach to my students now.

Make 3/4 x 3/4 x 12" hardwood stick. Drill a hole somewhat centered in one end and insert a brass #8 x 1" round head wood screw about half way. UNPLUG THE SAW. Raise the blade completely up. Clamp this board in your miter gauge (if you determine that there is some slop in your slot to miter gauge, use a playing card to take up the slop) so the screw head just about touches the blade at the front. Now rotate the blade by hand and determine which tooth is the closest. Adjust the screw in or out until it just touches this tooth. Mark this tooth. Rotate the blade so the tooth is now at the back of the table and move the miter gauge/stick assembly to the back and see if it touches the marked tooth to the same extent. If it doesn't, adjust the trunnion (if a contractor saw) or the tabletop (if a cabinet saw) until it does.

For a contractor saw, first use a small c-clamp on the rear trunnion and cradle to keep the assembly from moving. Then loosen the two rear trunnion bolts and one front trunnion bolt. Slightly loosen the other front trunnion bolt and use a stick to tap the trunnion until the blade and screw lightly touch. The blade does not move directly around the center so you will need to repeatedly go back to the front of the blade, readjust the screw, and then again measure the back. Be sure to check after tightening the trunnion as the trunnion frequently moves when being tightened.

For cabinet saws, loosen the bolts that hold the tabletop and tap one corner until things come into alignment.

The same adjustment gauge can be used to set the fence parallel to the miter slot. Slide the miter gauge to the front of the table and move the fence over to the screw head and insert a playing card between the screw head and the fence just so you can move the card as it touches both the fence and the screw head. Now move the miter gauge to the back of the table and see if you have the same feel when you insert the card. I like my fence absolutely parallel--if you want to have a slight opening to the fence, you can easily estimate the opening by adding a thickness of paper to the card.

I always show my students with a dial gauge that their adjustments are within .001 - .002.

You can also use the same gauge to measure blade runout by using a $5.00 feeler gauge.

Finally, after you are satisfied with the above adjustments, check the position of the splitter to make sure it is exactly in line with the blade.

Bottom line, there is no need to spend more than the $0.05 for the brass screw.

The second, and most likely issue is with your saw blade. You don't say exactly which Freud blade you are using but if your oak is more than 3/4" thick you should be using a true rip blade that has 24 teeth. GP or combo blades have a shallow side taper to give smooth edges to the cut line. However, this low clearence generates heat and will burn hardwoods.

Do the tune-up first. If you still get burning, get the proper blade.

[Harry Goodwin]

I had a rather expensive well respected blade that only burnt cherry and the tech fellow suggested raising the blade whiich largely cured it. I have not had a problem on only one side. Harry

[Dale Thompson]

Brad,

99% of the probable causes have already been covered but I will add one more highly unlikely cause. Are your oak boards STRAIGHT? Even a bit of a twist can cause some severe burning. :( :) Just a voice from the wilderness. :)

Dale T.

[Thad McCulloch]

One more suggestion to add to all the others. Judging by your 2nd picture, it appears that there are spots on the board where the blade may have lingered longer and given you that always attractive semicircular burn pattern. Are you able to keep a nice constant feed rate as you push the board thru the saw, or do you find yourself starting and stopping because you need to change your grip, or reposition push blocks, or whatever? A non-constant feed rate will make whatever burning you have worse (at least it always does for me).