Not sure if this is to be expected or not, but I’m noticing some blade marks when ripping wood on my table saw. Doesn’t matter the species, the marks tend to appear on the lower half of the piece, ie the side closer to the table. I’m using a Freud thin kerf rip blade, fairly new and the teeth are clean. Blade is 90 degrees to the table and the fence is parallel to the blade (actually about .001 further from the blade in the back). Blade height is set to where about 3/4 of the carbide is above the top side of the stock.
The blade marks aren’t terribly deep, but it seems like this hasn’t always happened. From the direction of the marks, the rear edge of the blade is causing this. Rate of feed doesn’t seem to affect it. Is a certain degree of this to be expected when using a rip blade because of fewer teeth, or is something in my setup causing it?
Replies
Are the marks worse on one side of the cut than the other (i.e. the waste side v.s. the 'good' side)? How many teeth on your blade?
It sounds like you're 'fighting' the cut by pushing the board slightly off-line with the blade. A thin kerf blade will flex a bit more than a regular blade so the blade wants to twist slightly then straighten up - causing those marks.
That 0.001 inch off in your fence may actually exacerbate the problem if you're holding the stock tightly against the fence. Your board isn't parallel to the blade rotational centerline.
Is your blade sharp? Is it really 90 deg. to the table? Is the blade still flat, not bent as a result of some previous operation? Is the motor arbor still true, with no wobble? Is the fence still near parallel to the blade? If it cut fine before, these seem to be the only changes that might have affected the outcome now.
I agree with Dave on the setting of your fence. Has your fence always been near parallel to the blade? A difference of just .001 at the back of the blade doesn't seem like enough to keep the piece from pinching between the fence and blade. Try opening the fence a bit more, perhaps 1/128" to 1/64". It would be safer, reducing the chance for kickback, and should relieve the sawn edge of the more serious saw marks.
tony b.
The 90 degree statement doesn't make sense to me. This would mean a beveled edge should not be clean
16 years after receiving good advices, he might have figured the problem.
right
Any chance you might be using a roller stand for outfeed? If you are and the roller isn't exactly perpendicular to the blade, that can cause your stock to pull slightly to one side at the back of the fence.
If you build it - he will come.
I just fixed a similar problem on my Unisaw. I'd changed the arbor bearings a while ago and when I re-assembled the arbor I hadn't tighted the grub screws holding on the belt pulley sufficiently. There was enough play to cause faint blade marks on the lower half of a cut face.
You may want to check to see if there is any play between the pulley and the arbor. You'd need to slack off the belts to check.
A little Loctite works wonders.
Hopefully your fixing problem is simpler than this.
Good luck
Tim
Soon-to-be furniture maker
Port Townsend, WA
I seem to have more issues with thin kerf blades than full body ones. When you check fence alignment, are you measuring to the blade or the miter ways. Even fully raised, measuring to the blade doesn't give a long point of reference. Everything about the saw will improve if your blade is parallel to the miter ways. I raise the blade and place a straight edge against it, then measure from the straight edge to the ways. The blade should be dead on to the ways. Now you can check fence alignment to the ways. I agree the back of the fence should be slightly more, I can't see .001 so I use the thickness of a mark on my tape or rule. The best rip blade I own is a triple chip Systimatic. Many times I have to hold the edge in the light just right to tell the cut edge from the jointed edge, just in case I forget to mark which is which. A perfectly tuned saw won't compensate if you don't have a perfectly straight edge against the fence and keep it tight.
Beat it to fit / Paint it to match
This should not be happening with that Freud blade, which is the one I use also. First of all, I'll stick my neck (or tongue, LOL) out and say that I totally disagree with any need to "toe out" the end of your fence.
I'd set that fence perfectly parallel to the blade, then double-check your splitter and make sure that it's (a) in line with the blade and (b) 90* to the table. If you're using a square only to check your blade you might want to do a cut test** to confirm that it's 90* to the table.
Are you using a featherboard in front of the blade? If not, give it a try. If your feeding technique is a little off, the FB might help.
**Take a board about 2" wide, stand it on edge and cross-cut it. Lay the two halves face-down, just as they were originally joined, then roll one side over to the other face. Any deviation from 90* will be multiplied by two, showing a gap if the edges are lined in a straight line.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Coleman -
How thick is the stock you're ripping? The thin kerf blade ~might~ be OK for up to 3/4" but anything thicker I'd suspect heat causing the blade to deform ever so slightly. Are you using a blad stabalizer with the thin blade? Whenever I do use a thin kerf blade, I add a stabalizer which seems to help. Otherwise I stay with a full kerf blade for most of my ripping. In fact I ripped some purple heart this afternoon with a full kerf Freud blade and it came out spot on, practically glue ready.
From Beautiful Skagit Co. Wa.
Dennis
I just purchased a new Forrest WWII thin kerf and was having trouble with burn marks. Called Forrest and they RECOMMENDED that I check my fence and to be sure it is open a few thousanths to guarantee that the blade is not cutting on the upstroke. This will not affect the dimension of the board you are ripping because the cut is made at the front of the blade and as another poster suggested, it is much safer in regards to kickback.
The End
Dan
Overworked, underpaid and under appreciated. The perks of being middle class and educated.
“[Deleted]”
Cole, I spent several hours today making sawdust (about 4 gallons of red oak sawdust) via ripping red oak planks. I'm probably using the same Freud blade you are.
How long are the pieces you're ripping? Since most of my pieces were long, I wood-clamped a 72" level to my fence (48" level would work). This is a popular technique to enlarge the fence. As already mentioned (by Forest girl?) I also used a featherboard to keep the board from drifting away from the fence...and then I tried to be careful about keeping it up against the fence as I fed it.
I had about 3 bad cuts. One was a plank with a bad edge (wedge shaped offcut was getting wedged between the featherboard and blade). Second one I let the plank ride up the fence a bit, and a small section didn't get cut through (and then got stopped by the splitter and wedged by the anti-kickback claws). Third one I left some blade and burn marks because I had started the cut with the convex side against the fence instead of concave.
Assuming I have my terminology correct... by trying to rip with a convex surface against the fence, it was basically trying to rock around the curved convex surface and playing he11 with my cut. If I'd had the concave side against the fence, there would have been much less grief.
jt8
The reason so many people never get anywhere in life is because when opportunity knocks, they are out in the backyard looking for four-leaf clovers. -- Walter Percy Chrysler
Not sure what I am missing in these discussions,in so much that if that happened to me I would go to the jointer and buzz the offending marks out,having allowed for the possibility.
Some pieces due to their size and use cannot be run on a jointer afterwards. For example, I just made some 1/4", quarter round and some small outside corner trim in an L shape. Last week I ripped 800 LF of 1 x 10 x 16' red oak baseboard, the pieces were not all perfectly straight nor did the bottom edge need to be pretty. You do need the back of the fence off set just a small amount to prevent the back of the blade from contacting the work. If you have it too tight, you will get pinching or burning, you can't always use a splitter, like in the L cuts, above. Some table saw users don't have jointers.Beat it to fit / Paint it to match
Thanks for all of the input. After fiddling for quite a while yesterday, I was able to minimize the marks by slowing the feed rate waaaaay down. Blade is sharp and is 90 degrees to the table, as is the splitter. Fence fades away just a bit at the rear. Not cutting long pieces so no outfeed roller, but will keep that in mind in the future.
I don't own a jointer so I like my rip cuts to be as clean as possible. Possibly something in my feed technique that became negligible when I slowed the feed rate down. I'll pay some close attention to it today while playing around a bit more.
Really appreciate all the input. I posted this message on several other forums and got some good suggestions, but got a whole lot more here.
Coleman, I think we'd still be interested in know how thick the stock is.
I still have a haunting feeling there's something out of alignment here.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Install yellow board buddies or use a powerfeed. You are getting burn marks from the pause when you shift hands when feeding the board. Some wood tends to burn more easily than others, cherry for example.Board buddies will help greatly, a 1/4 hp or more powerfeed is best but not essential for a home shop.
mike
My 2 pennies worth - set the blade so it just clears the upside of the boards. Helps stop blade flexing.
Mikaol
Most saws with any age on them could benefit from new arbor bearings.
Very few come with good quality bearings to start.
I've replaced most all my tools bearings with better ones and have seen a difference. Some of my newer machines had poor quality ones from the factory. They're some real junk bearings out there.
“[Deleted]”
I hope this poor fellow has fixed his problem by now. Waiting by his computer for 16 years, which is running XP, looking for that silver bullet. I also wonder why no one suggested that a good hand plane or a jointer would allow him to finish the project while he waits for a solution.
And now it is back on page 1, thanks to ysu.
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