Ripping problem : Board squeezing saw blade and stopping motor during rip

[dss2]

I have a problem. I am ripping a 10/4"x9" hard maple board and my table saw blade keeps getting squeezed by the blade and stops the motor. The board is straight and has been jointed, the problem is that the board seems to want to warp toward the blade when cut. What do I do about this? I have a Delta 36-982 contractors saw running on 220V and a brand new

24tooth Freud thin kerf blade so power is definitely not the problem. I have done this cut before on other boards with the same dimensions with no problem.

[GarageWoodworks]

Are you using a splitter?

[Swingman]

wrote

You're most likely dealing with "reaction wood":

've very lucky that it didn't get thrown back at you.

Throw that particular board in the direction of the scrap pile and be done with it, as it will likely always be prone to warp and/or twist.

... and start using a "splitter" on your table saw, it will safer all around.

[George]

It's the wood. Look at the annual rings may tell the tale. If you've got a lot of curve, you could be releasing tensions that cause the kerf to close. Case-hardening, or as mentioned, reaction wood from a branch load or curved growth can cause this as well.

One of the reasons why splitters are used, because the wood binds on them versus the blade. If you have a bandsaw and just a bit of talent at following a line, you might be able to get the pieces apart, but if both are curved, they'll be pretty much useless anyway.

[Leon]

I would say power and the thin kerf blade are part of the problem. If you had adequate power you would not be stalling the motor. The thin kerf blade is probably causing the problem in addition to your wood probably not being dried properly.

"IF" you have had no problems before, then your wood is probably the problem. Not properly dried. The use of a splitter will help however you can also use wedged shaped shim stock to hammer in the kerf behind the blade to help keep the board from wanting to close back up.

That said, the thin kerf blade is probably also working against you. If you are cutting deep and the blade does not remain "flat" it will flex "as thin kerf blades do" and rub against the blade as you are witnessing. Once a thin kerf blade begins to flex it tracks in the wrong direction and the situation becomes worse. I would immediately try a regular kerf blade and go a little slower.

[GarageWoodworks]

I have done this before and it works. Be sure you put the wedge far enough behind the blade. If the blade hits the wedge, it will throw the wedge at you faster than you can say 'what the f--- just kicked me in the stomach?' . Also DO NOT put the wedge in while the blade is spinning. Start the cut until it starts to bind, turn the saw off, then put in the wedge and re-start the saw.

[dss2]

After reading all the posts it sounds to me like reaction wood is my problem. I was using a splitter when this problem happened. I did however get through this particular piece though (see below). I am not crazy about the idea of throwing the wood out since it was over $100 and I'm pretty cheap (that $ could be a new tool).

I'm pretty sure it was dried properly. I purchased it from Owl Hardwoods which is a pretty good chain in June. I have left it to dry on a drying rack with 1/2" spacers between each board for an additional 4 months in my basement and the AC has been on all summer to remove humidity (there is no exposed ground/gravel in the basement, just concrete all around and 2 covered and sealed sump pumps)

The method I used to cut this wood was:

-Remove the splitter.

-Pull the board off of the blade

-Lower the blade and rip 2/3 the height of the board on the first pass (this would not allow the reactive wood to twist)

-Flip it over and cut the remaining 1/2 o the height (it did twist/ warp, but there was far less exposed blade so it did not bind)

As was suggested that particular piece was smaller than intended due to the multiple passes so I made it straight again on the jointer and will save it for a later project. I started over with some of the remaining wood from the original

9" (minus 2.5 from the messed up board). This time I ripped it using the method above with an extra 1/4" so that I could fix any warping on the jointer and end up with the correct dimensions.

Anyone see anything wrong with this? CarlC suggested that it will always be prone to twisting... Do you mean after it is finished? If it is now cut, square and straight will it twist some time in the future (like after my project is completed and sealed)? The wedge idea sounds like a good one too, I did think of that but there was not enough room when using the splitter (the wood had not made it past the splitter yet). Thanks for all the advice, Dave

[Allen Roy]

Did you seal the end grain when you started to dry it? If not, I agree, it will always give you problems.

Allen

[dss2]

Allen, It was already dried when I purchased it (although I do not know the %). But just to make it a little dryer I stacked it so that air can circulate. I did not seal the end grain. Should I have done this when I purchased it? Or should I do it now? Or were you assuming I purchased it green? I will be assembling this into furniture in the next few weeks and do not want it to warp after I assemble it. If I must discard the wood I suppose I will have to take the loss and try to make sure I inspect the wood more carefully for this potential problem. Thanks again, Dave

[Edwin Pawlowski]

I'd let it sit for a couple of weeks and see if it moves now that it was cut. Once in place, it will probably hold OK as it will be attached to other pieces. Sort of like framing lumber if you build the wall right away.

OTOH, I've heard a couple of stories where furniture would self destruct two years later because wood moved or was not allowed to move properly with seasonal changes.

[George]

Millions and millions of BF of hard maple leave the woods, mill and kiln with nothing more than a species/grade spray paint slash across them around here. End checks have nothing to do with twist.

If the new form is stable for a few days it should be stable for the future, especially with some finish added to slow the uptake and loss of moisture to a crawl. Some of the most dimensionally stable woods in my shop are the curly stuff. Tighter the figure the more stable.

I assume (yeah,yeah) that a dealer means it's KD, so your operator could certainly have made a mess of things for you by putting a 2" piece in with a

1" schedule. "Case-hardening." See Hoadley or for some information on stress created by poor kiln practice. It would take a few years of cycling or a rehydration to break it.

[Swingman]

wrote

You just need to be aware of the pitfalls so you can make a relatively informed decision on what to do with that particular piece.

What is fact, according to you, is that this particular piece exhibited enough internal stresses when it was cut to bind your table saw blade with a splitter installed.

You may have already released all/most of the stress on the first cut, maybe not. That's the question which only time will tell ... do you want to put that piece in critical place in a project worth doing, NOT knowing what it will do in the future?

That said, I don't think I've ever run across a piece of wood that couldn't be used some place in a project ... even it was just cut up to make floating tenons.

It's a pretty good possibility that you've found out the answer to your original question ... what you do with it is your call.

[Allen Roy]

Sealing it now won't do anything. I assume by dried it means kiln dried and that can vary by operator to operator. It could have had as much moisture as a 2x4 from the borg as far as anyone knows. I agree that at this point it will be hard to tell what it will do.

Allen

[Adam.Jaksha]

If you use a hold down and featherboard to control the cut, you can cut partially through the board until it is slightly past the blade, then raise blade to cut thru with your free hand, leaving an uncut spacer tab at the front of the board to keep the board from pinching the blade. I saw this at the Grip-Tite feather board booth at the woodworking shows. He was ripping a twisted junk board from the cull bin that really wanted to pinch- used a splitter they make for 10 bucks. It is just a simple pin behind the blade that moves left and right and was only a half inch high. I bought their featherboards, and they tossed in the splitter for free.