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Thread: Ripping woes.... bad technique?

  1. #1

    Ripping woes.... bad technique?

    Long time since visiting, trying to get back in the saddle!

    I have somewhat an open question, but looking for suggestions/ideas that may help me, if you don't mind.

    I am a bit at a loss and frustrated. Since I got a Sawstop (3HP) a couple of years ago, I haven’t really asked much of it at all until yesterday. I needed to rip an 8/4 30” long piece of soft maple and the saw really struggled, to a point that I had to stop the saw as I was getting quite nervous having to push so hard.


    Of course my first thought was that I was having alignment issues, so I checked and checked again, even made minor adjustments to the fence and checked the blade alignment. They are absolutely spot on (and I tried the fence to be absolutely parallel and then made it 1/64” wider at the end, as the manual suggests as an alternative). I used the splitter, and also tried with the the riving knife. I raised the tooths so the gullets show, and also tried with just the teeth showing. I even changed the blade (I have a fairly new WW-II, which is as good as it gets, but I even tried the stock Sawstop, which is inferior, but was 100% new). Yes, they are both 40 teeth hybrid cut… but honestly; the machine was struggling even with 1” test boards.


    To be fair, even as the fence and blades were spot on, it felt to me that as I fed, the board started to pivot a bit (my stock had fresh edges and flat face from the jointer, though). I was also using a magna-board featherboard just *in front* (edited) the blade… and that actually felt like it was making things worse.


    Right now, after all the adjustments, it has shown some minor improvements… but I can’t imagine I should struggle in pushing that hard with that 3HP monster and a good blade (not just the 8/4, but the 4/4... and no, the stock is not under a ton of stress and doesn't seem to be pinching anything more than normal.


    So, any ideas what I am doing wrong? Look at the burn marks after forcing to finish the rip on the boards. And this is the second attempt… the first one burned much worse! Pushing them through was anything but fast. It was slow and had to push hard once the blade was fully engaged.


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    Last edited by Augusto Orosco; 02-22-2021 at 3:34 PM.

  2. #2
    Do you still have trouble pushing through without either the blade guard or riving knife? That is, without ANY kind of splitter?

    When I got mine, the RK was a little thicker than the blade I was using; I had to grind my rk down to accommodate the thinner kerf.

  3. #3
    Join Date
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    The burn marks suggest the blade and fence aren't parallel, or the splitter/riving knife is pulling the wood into the side of the blade. On the other hand, taking so much force to push the wood through the blade suggests the splitter/riving knife is thicker than the blade or is pinching the wood against the fence.

    John

  4. #4
    Quote Originally Posted by Augusto Orosco View Post
    ... I was also using a magna-board weatherboard just behind the blade… and that actually felt like it was making things worse.
    ...
    I assume this is a typo and you meant "feather-board", if so, I would never install it behind the blade. Whatever relief is created between the (now split) boards, the blade, and the fence will be compressed by the pressure from the feather-board.

    If needed, I place mine right at the front of the blade - perhaps 0.75" to 1" overlap of the blade if necessary with small/short stock.

  5. #5
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    First, I assume you've verified that the blade is not dull or have damaged or misaligned teeth. If not, it's worth checking. Also verify that it's an appropriate blade for ripping.

    Assuming those aren't issues, then as others have suggested, the thickness of the riving knife vis-a-vis the blade could be an issue.

    But I would also check that the RV is not itself twisted or badly mounted. A riving knife pushing the stock into the fence could account for the tough cutting and the burning (by causing your pressure on the piece to rotate the stock into the blade's side). If the riving knife is the problem, BTW, you should be able to tell by when the resistance to cut appears. If the saw is cutting poorly even before you get the workpiece all the way through the blade, then it's likely the blade, not the knife.

    One thing is for sure - you should be able to go through 8/4 soft maple with a 3HP saw and a good, sharp ripping blade like silk, unless the workpiece is a complete mess of reaction wood that is directly binding on the saw blade or riving knife.

  6. #6
    Join Date
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    can't help but I cut 8/4 maple and walnut with no issues when I made a large cutting board a few months ago and that was using the standard SawStop blade

  7. #7
    Sorry, I was a typo, and worse, I misspoke. Yes, it's a featherboard and it's positioned "behind" (as in, closer to me, before the board engages the blade).

    My bad!
    Last edited by Augusto Orosco; 02-22-2021 at 3:26 PM.

  8. #8
    Thanks guys. I will look further into the RK alignment. I checked earlier and I know it's thinner than the WW-II blade I am using, but perhaps it's not properly aligned as indeed that's where I start getting into trouble. I had hesitated to test without either the RK or a splitter, because I was nervous about kickback giving how hard I was pushing. But as I have checked both blade and fence for alignment, I think I will give that a go first as seems to be the easiest thing to check.

    The blades I have tried are the stock Sawstop blade (which albeit not great was brand new) and the Forrest WW, which is not new, but barely has seen a few linear feet of action. Both are 40 teeth and rated as a combo, so I can also try a true ripping blade later.

    Thanks for the help!
    Last edited by Augusto Orosco; 02-22-2021 at 3:36 PM.

  9. #9
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    Try this.

    1. Rip your 8/4 board so you take off just a tiny bit on left side (blade side). After you have ripped the board, we know that the board is properly sized for the blade. Move the board forward and back to see if it deflects the riving knife.This will test the alignment of the right side of the riving knife.
    2. Now, lower the blade, move the fence to the left of the blade and repeat the test

    If you see any deflection of the riving knife as the leading edge of the wood engages it, you will know if you have a problem.

    Another simple test would be to remove the riving knife and rip a kerf partway through a piece of MDF. Is the kerf big enough for the riving knife?

    To test blade alignment with the fence, just look at the saw marks. There should be roughly equal scratches from the front and back sides of the saw.

  10. #10
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    Have you tried a ripping blade like a 24 tooth FTG grind?

    8/4 is far too thick to rip with a 40 tooth blade.

    Check your saw alignment as well.............Rod.

  11. #11
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    Switch to a piece of plywood. The solid stock may have internal stresses and complicating the situation. Also I agree that a WWII is not a good ripping blade. How old is it and have you had it sharpened. It's not a thin kerf WWII is it?

  12. #12
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    Quote Originally Posted by Augusto Orosco View Post
    Sorry, I was a typo, and worse, I misspoke. Yes, it's a featherboard and it's positioned "behind" (as in, closer to me, before the board engages the blade).

    My bad!
    You are still misspeaking, a featherboard closer to you is normally referred to as "in front of" the blade. It's difficult to get good advice if people can't picture what you are doing because of incorrect terminology. With an underpowered saw (not your case), dropping the blade down and cutting half way thru then flipping end for end keeping the same face against the fence can prevent the saw from bogging down. You could try this w/o the riving knife.

  13. #13
    Quote Originally Posted by Doug Garson View Post
    You are still misspeaking, a featherboard closer to you is normally referred to as "in front of" the blade. It's difficult to get good advice if people can't picture what you are doing because of incorrect terminology. With an underpowered saw (not your case), dropping the blade down and cutting half way thru then flipping end for end keeping the same face against the fence can prevent the saw from bogging down. You could try this w/o the riving knife.
    You are correct, I was still misspeaking. Now corrected in original post. Sorry for the inconvenience.

  14. #14
    Check if the wood is flat after being ripped, or if it has any curve. If it is not completely flat, it may be that the wood has internal tension that is being relieved. Soft maple tends to be a stable wood (unlike hard maple), but like any wood, it can have differential moisture or, as noted above, tension wood in it. That can cause the wood to bind during the cut.

  15. #15
    Quote Originally Posted by Roger Feeley View Post
    Try this.

    1. Rip your 8/4 board so you take off just a tiny bit on left side (blade side). After you have ripped the board, we know that the board is properly sized for the blade. Move the board forward and back to see if it deflects the riving knife.This will test the alignment of the right side of the riving knife.
    2. Now, lower the blade, move the fence to the left of the blade and repeat the test

    If you see any deflection of the riving knife as the leading edge of the wood engages it, you will know if you have a problem.

    Another simple test would be to remove the riving knife and rip a kerf partway through a piece of MDF. Is the kerf big enough for the riving knife?

    To test blade alignment with the fence, just look at the saw marks. There should be roughly equal scratches from the front and back sides of the saw.
    Very helpful, will try that. Thank you!

    Quote Originally Posted by Rod Sheridan View Post
    Have you tried a ripping blade like a 24 tooth FTG grind?


    8/4 is far too thick to rip with a 40 tooth blade.

    Check your saw alignment as well.............Rod.
    Thanks, Rod. I have a new 24 tooth Rip Blade lying around. I will try it, too. Although I would expect that my more pedestrian rips (4/4 rips) wouldn't have that problem

    Quote Originally Posted by Richard Coers View Post
    Switch to a piece of plywood. The solid stock may have internal stresses and complicating the situation. Also I agree that a WWII is not a good ripping blade. How old is it and have you had it sharpened. It's not a thin kerf WWII is it?
    Upon experiencing the problem, I tried with other woods (including 4/4 hard maple). But haven't tried plywood, can try that, too. The WWII has seen little use and I don't see any damage to it. Probably have gone through less than 100 linear feet of wood (I use my bandsaw and hand tools more heavily than the saw). It's the WW-II thick kerf "for Sawstop Table Saws". 10", 40T.

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