Challenge with table saw

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33
I have recently been running into difficulty ripping boards thicker than 4/4. It seems that the boards tend to move away from the far end of the fence while tightly abutting the back end of the fence.

At first, I assumed that the table/fence was out of alignment with the blade. However, when checking the blade to miter slot (assuming I am not making a mistake) it seems to be within 2-4mm. As to the fence, I have aligned it to the miter slot; yet the problem remains. Even tested by skewing the fence both right and left at the front to see if it has an impact and it does not seem to.

I noticed while ripping an 8/4 board yesterday that there was a fair amount fo twist as the board was cut presumably from the release of internal stress. But this doesn't appear to be a consistent situation.

Would appreciate any thoughts as it it is quite a bit of work dealing with the burn/gouging as well as it is likely very unsafe.

Thanks much
Sal
 
as for internal stresses in wood you can get alot of movement in a cut if the wood your cutting is stressed a great deal and there isnt much to tell you if it does or doesnt till you cut it. generally a twisted board to start with is a sure sign of more trouble when cut open..
 
Jim,

Sorry, I mis-wrote the the tolerance. I should have said/wrote .002 to .004 inches! Agree that at 2mm it would be the issue.

Thanks
 
A dull blade can also cause that problem.

Along with that would be to measure from the blade to the fence both front and back. When you do that make sure you use the same style tooth on both ends. Aligning the fence to the miter slot is not doing anything for you. The fence needs to be true to the blade.
Also check for blade wobble.
 
All posters have valid points, but Larry gets my vote. I once had a student rip a 2x4 in half. She stood it on end and left it for the day. The next morning the 2 pieces looked like corkscrews. I wish I had a picture. From end to end of a 8'er there were at least 2 revolutions. I know you are not using construction grade material but it makes me wonder--could it be reaction wood?
 
thanks for all the ideas. The blade is new with a 40T to help with ripping. I've have had the problem with both soft maple and walnut. The boards were all jointed/planned before ripping. No twist untill the cut. Assuming internal stress, any recommended ways to deal with it?

for the last piece of 8/4 walnut, I cut halfway through and then flipped it to cut from the other end. given the tightness and the board effectively jamming against the back end of the fence, it seems to be a dangerous action.
 
thanks for all the ideas. The blade is new with a 40T to help with ripping. I've have had the problem with both soft maple and walnut. The boards were all jointed/planned before ripping. No twist untill the cut. Assuming internal stress, any recommended ways to deal with it?

for the last piece of 8/4 walnut, I cut halfway through and then flipped it to cut from the other end. given the tightness and the board effectively jamming against the back end of the fence, it seems to be a dangerous action.

40 teeth is pretty high for 8/4. Excess heat can cause strange things to happen, especially in moist wood. Try 24T to 30T. Make sure your splitter/riving knife are aligned too.
 
Thank you for all the suggestions. I started ripping with a short fence. Seems to provide some benefit. Will need to cntinue to test.
 
Sal,

This sounds a little problematic to me. I can only think of four surfaces involved: blade, table, fence, splitter. Assuming they're all aligned (I once had big problems with a splitter), and it's not simply a problem with reaction wood (you said it happened with multiple pieces), the only things I can think of are feed and support. I've had problems with obstacles in my small shop that made it difficult to feed very long workpieces precisely. And I've had problems supporting very long pieces properly, which led to many frustrations, blade burn, and skew, especially near the start and end of the cut.

Good luck with your testing...

Best,

Bill
 
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