Wood wants to lift when beginning a cut on table saw - Woodworking Talk - Woodworkers Forum
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post #1 of 34 Old 12-29-2019, 01:23 PM Thread Starter
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Wood wants to lift when beginning a cut on table saw

Got a new Metabo table saw and after aligning the blade and fence still having issues with wood want to lift when beginning the cut. I have had several table saws in the past and donít remember the piece doing that so easily. The spinning of the blade should push the piece downwards on approach? But for some reason, it tries to lift and ride over the top of the teeths. There is no issue with binding yet since the piece is just starting to be cut.
Installed a new Dewalt 60tooth blade and same problem. Thoughts.
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post #2 of 34 Old 12-29-2019, 02:31 PM
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It should NOT lift .....

Possibly you got the blade on backwards which might cause it....?
The teeth rotating downward toward should pull the work into the table surface...That's what happens on my saws.



If you messed with the wiring that would also explain it, but not very likely.


A negative hook blade possibly?


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post #3 of 34 Old 12-29-2019, 07:13 PM
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Or it's a very dull blade. Raise it up higher.

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post #4 of 34 Old 12-29-2019, 07:56 PM
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The blade is rotating downward. Or at least it should be. Almost reads like the motor is running in reverse.


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post #5 of 34 Old 12-30-2019, 12:52 AM
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What size piece are you using? length, width and thickness?
Was wondering if the piece was small and light weight and the wind from the blade was lifting it.

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post #6 of 34 Old 12-30-2019, 01:09 AM
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I think the blade is wrong for what you want to do.
Check the details on the blade and then look up its designed usage.
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post #7 of 34 Old 12-30-2019, 11:26 AM
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Its not something inherently wrong with the saw, its related to the blade and the wood. Could be the wrong blade, like the negative hook angle mentioned, so check that.

I've experienced this when the blade needs sharpening and also if I'm trying to rip with a crosscut blade (IOW too lazy to change it). Also when cutting thin stock.

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post #8 of 34 Old 12-30-2019, 12:02 PM
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I know this is a dumb question, but have we verified that the saw table is flat?
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post #9 of 34 Old 12-30-2019, 12:41 PM Thread Starter
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It is a new blade and going the right direction. When I put a large piece in, it starts to cut but then wants to ride up on the blade. I pulled the piece out there is no binding on the cuts.
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post #10 of 34 Old 12-30-2019, 12:51 PM
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Raise the blade more. 1/2" above the wood should stop it. Full tooth above the wood is about the minimum you can really do and that's for safety but can still push the wood away.
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post #11 of 34 Old 12-30-2019, 03:53 PM
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I would try raising the blade an inch above the wood and try it.
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post #12 of 34 Old 12-30-2019, 06:18 PM
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After seeing the photos, I agree with the others, raise the blade. Even though you are cutting off what looks like a tongue (tenon, protrusion, whatever), I wonder whether the blade is interacting with the inside edge of the full board too.

Here is a little reminder that I copied from Forrest's website. I printed it and keep it taped inside a shop cabinet door for reference:

* Rip Cut: Raise the blade high. The carbide stays cooler and expands less during the cut.

* Crosscut Solid Wood: Raise the blade one inch above the top of the wood.

* Plywood: Set the blade height so that the bottom of the gullet is at the height of the plywood, to reduce or eliminate tearout. Cutting plywood is hard on blades and dulls them faster.

Some woodworking experts recommend raising the blade up to gullet height on all cuts for safety reasons. I think the idea is to reduce the amount of exposed blade that a person could contact. Forrest's advice seems more about best quality cuts and blade wear, while they accept a somewhat increased personal risk as a tradeoff. I would say that Forrest assumes you have a more professional competence, experience, and attitude towards safety. That's my opinion, nothing more.
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post #13 of 34 Old 12-30-2019, 07:43 PM
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Not the best photo for describing your issue ....

First, raise the blade so it 's above the wood about 3/4". The blade itself looks like one of those "safety" anti-kickback prevention types which don't really work well. Get a new Diablo 40 or 50 tooth blade, about $30.00 at the Home stores and try that. Come back again with your results. Finally your work piece looks like it's got a 1/8" gap under it, not good! All the work placed on your saw table should be as flat as possible to avoid a shift while making the cut.... a kickback "may" result if you aren't prepared for it.


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post #14 of 34 Old 12-31-2019, 01:49 PM
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Are you 100% sure the blade and fence are aligned parallel, too much toe-in could cause this.

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post #15 of 34 Old 12-31-2019, 03:59 PM
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Quote:
Originally Posted by woodnthings View Post
The blade itself looks like one of those "safety" anti-kickback prevention types which don't really work well.


Be careful with this conclusion. That anti-kickback design does exactly what it is intended to do...it limits how much "bite" each tooth is permitted to take at once. As a matter of fact, his "problem" is actually testament to the effectiveness of the design.

As was mentioned, the low blade height is what is causing the board to lift on feeding, but it is also the anti-kickback design that is "activating" (for lack of a better word) that helps foster the problem. When an un-cut portion of the wood is pressed into the anti-kickback gullet, the gullet is intended to push it back. But because the blade is so low, pushing back translates into pushing-up.


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post #16 of 34 Old 12-31-2019, 04:10 PM
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Quote:
Originally Posted by DrRobert View Post
Could be the wrong blade, like the negative hook angle mentioned, so check that.

Good point. I just took a closer look at the picture, and it does appear to be a negative hook angle crosscut blade. The blade is intended to be used on a radial arm saw or a miter saw, but not (specifically) for a tablesaw. That's not to say it can't be used, but just not for this particular operation. It would probably perform fairly well for breaking down sheet goods.


<EDIT> I've added the closeup picture I was using to draw my conclusion. I can see the negative rake on it. Coupled with the anti-kickback feature, it is clear that this is a mitersaw or radial arm saw blade.
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post #17 of 34 Old 12-31-2019, 05:53 PM
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Like I said in post no. 2 ......

Quote:
Originally Posted by woodnthings View Post
Possibly you got the blade on backwards which might cause it....?
The teeth rotating downward toward should pull the work into the table surface...That's what happens on my saws.



If you messed with the wiring that would also explain it, but not very likely.


A negative hook blade possibly?


Quote:
Originally Posted by Rick Christopherson View Post
Be careful with this conclusion. That anti-kickback design does exactly what it is intended to do...it limits how much "bite" each tooth is permitted to take at once. As a matter of fact, his "problem" is actually testament to the effectiveness of the design.

As was mentioned, the low blade height is what is causing the board to lift on feeding, but it is also the anti-kickback design that is "activating" (for lack of a better word) that helps foster the problem. When an un-cut portion of the wood is pressed into the anti-kickback gullet, the gullet is intended to push it back. But because the blade is so low, pushing back translates into pushing-up.


.
Quote:
Originally Posted by Rick Christopherson View Post
Good point. I just took a closer look at the picture, and it does appear to be a negative hook angle crosscut blade. The blade is intended to be used on a radial arm saw or a miter saw, but not (specifically) for a tablesaw. That's not to say it can't be used, but just not for this particular operation. It would probably perform fairly well for breaking down sheet goods.


<EDIT> I've added the closeup picture I was using to draw my conclusion. I can see the negative rake on it. Coupled with the anti-kickback feature, it is clear that this is a mitersaw or radial arm saw blade.

We got it figured out now!

It's not only the wrong type blade, but it set way too low no matter.
The lower the blade, there are more teeth there are tending to "push" against the feed pressure making it more difficult to feed. A higher blade has fewer teeth entering at a steeper angle pressing down against the material and cutting more efficiently. Again, it's about the physics and forces involved.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #18 of 34 Old 01-01-2020, 12:06 AM
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Hi


Am I the only one that has noticed that it looks like he is cross cutting using the rip fence. Does it push up on all types of wood or just that piece?
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post #19 of 34 Old 01-01-2020, 03:28 AM
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Actually .....

Quote:
Originally Posted by ajdragon View Post
Hi


Am I the only one that has noticed that it looks like he is cross cutting using the rip fence. Does it push up on all types of wood or just that piece?

Crosscutting would be easier than ripping with this blade. The use of the fence only matters when the size of the piece is too small or short to properly maintain good contact along the fence. A miter gauge with a fence extension is always much safer than trying to hold small pieces securely against the rip fence!


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The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #20 of 34 Old 01-01-2020, 10:13 AM
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I may be wrong but does it just raise up when you are cutting into a knot like in the photos above?

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