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What causes burn marks on the table saw

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Forum topic by Fireball posted 2398 days ago 13559 views 1 time favorited 12 replies Add to Favorites Watch
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Fireball

65 posts in 2701 days


2398 days ago

Just a quick question – when doing normal ripping operations, what would cause the wood to have intermittent burn marks?

Feed rate too slow? Too fast? Dull blade?

Please advise – thanks!


12 replies so far

View GaryK's profile

GaryK

10262 posts in 2622 days


#1 posted 2398 days ago

All of the above? Usually it’s the wood you are cutting. If it’s not perfectly flat of straight it could bind against
the fence. The wood could also be reactive. When cut the internal stress is relieved and it bends.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Scott Bryan's profile

Scott Bryan

27251 posts in 2456 days


#2 posted 2398 days ago

Another thing to check is your saw blade alignment. It should be parallel to the fence. If not then this will produce burning. It could also be something as mundane as a dirty blade.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View gizmodyne's profile

gizmodyne

1763 posts in 2724 days


#3 posted 2398 days ago

I agree: check the blade alignment and make sure you are feeding with a little bit of diaganol pressure towards the fence.

-- -John "Do I have to keep typing a smiley? Just assume it's a joke." www.flickr.com/photos/gizmodyne

View WoodworkersResource's profile

WoodworkersResource

33 posts in 2606 days


#4 posted 2398 days ago

All the above are great responses. The number one reason for burning on the table saw is usually that your blade isn’t parallel to the fence. This is a problems that’s pretty easy to fix.

I’ve got a free video on my website you can view that’s all on setting up and maintaining a table saw, particularly a contractor saw. All you really need to check for parallel between your fence and blade is a magnetic base with a dial indicator and a simply shop made jig.

If your interested you can view the setup video at:

http://www.woodworkersresource.com/video-blog/tlc-for-your-table-saw/

Hope this helps.

-- Craig, www.WoodworkersResource.com (Where Information meets Inspiration)

View rikkor's profile

rikkor

11295 posts in 2508 days


#5 posted 2398 days ago

Agreed, its generally binding because the blade is not exactly parallel to the fence.

View Fireball's profile

Fireball

65 posts in 2701 days


#6 posted 2397 days ago

Thanks for the responses and thanks to Craig for the link. I am supposed to be “working” right now, so will have to wait until tonight to take a look at that video. I’ll try to check the fence tonight and see if that is the culprit.

THe problem seems to have started all at once, so perhaps the fence got bumped out of alignment.

View gizmodyne's profile

gizmodyne

1763 posts in 2724 days


#7 posted 2397 days ago

Check the splitter on your guard too. If that is out of alignment it can pull the wood away from the fence as well. Adjust it.

-- -John "Do I have to keep typing a smiley? Just assume it's a joke." www.flickr.com/photos/gizmodyne

View Hawgnutz's profile

Hawgnutz

526 posts in 2710 days


#8 posted 2397 days ago

I have found that if you stop in your feed, the blade will burn the wood, too. Make sure your feed is a steady motion, not too fast and not too slow. And try NOT to stop. I have done this due to a piece binding between the fence and blade or the internal stress causing the wood to warp around the blade when it was being cut.

Some woods, like cherry, are notorious for burning when cut. Make sure your blade is new or sharp and appropriate for the cut. (e.g. Don’t use a 24 tooth rip blade for crosscuts.) If you have ot force the cut, something is wrong!

But, I beleive that the general concensus is that burniong occurs mostly from the fence not being parallel to the blade. So, that would be the first to check.

God Bless,
Hawg

-- Saving barnwood from the scrapyards

View DaveH's profile

DaveH

400 posts in 2412 days


#9 posted 2397 days ago

You can also get burn marks if you are not feeding smoothly. Some glues in plywood can cause burn marks.

-- DaveH - Boise, Idaho - “How hard can it be? It's only wood!”

View Fireball's profile

Fireball

65 posts in 2701 days


#10 posted 2396 days ago

Gents,

The following crude method was used to check the fence to blade alignment. Marked a tooth on the blade and brought it as far forward as possible. Measurement = 10” exactly. Rotated that same tooth as far back as possible, distance from tooth to fence = 10 1/32”

Seems like this is what i want as the fence is toed slightly out to help avoid kickback.

I also took the blade off and cleaned it up. I don’t think it was too dirty, but do you guys think that it had enough junk on it to compromise cut quality?

I’ll be back out to the shop shortly to reinstall the blade and make a few test cuts. Hope all goes smoothly (no pun intended!)

100_1653

100_1654

View jcees's profile

jcees

946 posts in 2433 days


#11 posted 2396 days ago

All good posts but you should FIRST check the blade’s alignment with the miter slot. If that’s okay THEN check the fence alignment with the slots. You can do all this with a 6” machinist’s combi square. Just make sure and register on the plate and NOT on a tooth. Get the blade-slot relationship dead-on and follow that up by making sure the fence-slot is perfect and Voila!

You mention allowing for toe-out with your final alignment, if you do make it slim, less than a 64th of an inch BUT with a caveat, a slight offset at the back of the fence won’t save you from kickback. A better solution is to install a riving knife or one of the aftermarket splitters. If you’re ripping into reaction wood, you NEED a splitter/riving knife to circumvent the inevitable pinch behind the spinning blade.

Also, not mentioned here but another must-have for safety are zero clearance throat plates. Make your own or buy them, you’ll be glad you did. And don’t forget to incorporate push sticks, sleds, et al to keep your hands away from that blade. Good luck.

always, J.C.

-- When one tugs at a single thing in nature, he finds it attached to the rest of the world. -- John Muir

View GaryK's profile

GaryK

10262 posts in 2622 days


#12 posted 2396 days ago

I make sure that the rear of my fence is about .015 farther away from the miter slot in the back.
This little bit relieves any pressure of binding.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

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