Table saw blade pinch

[Jay Basen]

I've started running into a problem and I hope someone can help me find a solution. I've read other posts on issues with pinching a blade on a table saw but I haven't seen anything that addresses exactly the situation I'm having.

Recently I've been ripping quite a bit of quartersawn white oak. As I rip the wood the blade bogs down until I have to hit the power switch and turn off the saw. After working the wood off the blade what I'm finding is that the wood on either side of the cut seems to be bending together which is binding on the blade.

I did notice that I had built up a good amount of pitch on my blade (a freud fusion) so tonight I cleaned the blade. I'm not sure if this could be contributing to the problem. I haven't had a chance to try ripping another piece of wood since cleaning the blade but thought I would post a message to see if there were any other suggestions as having the blade bog down like this is not a lot of fun.

Thanks in advance for the help

Jay

[Jim Summers]

If you have a splitter or riving knife that might help. If one of those is already in place then I am not sure what else to try. Sounds like you are getting into a potentially dangerous situation so watch out.

HTH

[steve reeves]

I'd check your fence for proper alignment with the blade... the fence could be "toed in" a bit towards the back of the blade.

If so this is indeed a dangerous situation that you should rectify immediately.

[Jay Basen]

Thanks for the reply. I do have a splitter in place with a guard to keep the wood from kicking back.

I'm well aware of the danger involved here. I was once hit with a piece of kicked back wood and try to do everything I can to avoid repeating the experience which is why I want to solve this as quickly as possible.

Thanks again for your reply.

Jay

[Dennis Puskar]

If the wood is pinching the blade then you need to insert a wedge in your kerf after you start the cut.

Dennis

[Jim Summers]

Maybe try to make a splitter that is another 1/64th thicker or something.

My old Dewalt benchtop ts had a way to shim the blade guard that doubled as the splitter in one direction. Seemed like it would shim way from the fence and then have the fence toe out (wider at the back) by about .001 or so.

HTH

[Jay Basen]

Thanks Steve. Just to make sure before I replied back, I double checked my fence alignment and it is indeed toe'd out about 10 thousands of an inch from the front to the back of the blade.

Thanks again

Jay

[Jay Basen]

Interesting idea Dennis. Thanks.

Just so I understand, are you suggesting that once the wood clears that back of the splitter that I stop the saw insert a wedge, restart the saw and continue the cut?

Thanks again for your help

Jay

[steve reeves]

Jay, what is happening is once the piece passes the blade the misaligned fence is forcing the piece back into the "Cutoff"... that's what's causing the binding. This is happening behind the splitter..

It's almost always the fence being toed in... if anything the fence should be toed away from the blade but just a little bit. I usually set mine at a couple thousandths out at the rear of the blade.

I'd bet good money that adjusting the fence cures the problem.

[glenn bradley]

Maybe try to make a splitter that is another 1/64th thicker or something.

My old Dewalt benchtop ts had a way to shim the blade guard that doubled as the splitter in one direction. Seemed like it would shim way from the fence and then have the fence toe out (wider at the back) by about .001 or so.

HTH


Jim's shares my thoughts. If your splitter is not as wide as your blade teeth it is not going to do the job. Many factory splitter/guards use thin sheet metal which isn't enough.

I know folks who start the cut and then reach over the blade to drive a wedge into the kerf. Gives me the heebies but folks do it. With the cost of the material I would be tempted to pick up an MJ splitter or other proper sized one (that is if your's is not thick enough).

[glenn bradley]

Take some calipers and measure a tooth or two on your blade. Now measure the splitter thickness. If it is not the same or very close, your splitter is not doing it's job.

[Jason Beam]

I can't help but wonder if the board's that reactionary as to bog down the saw, is it gonna be any good once you finish the cut? It sounds like it's gonna be a banana comin' off that blade.

Sounds like some pretty tense wood. I'd cut it oversized and let it settle a few days and then trim to finished size. Unless of course it moves so bad that the finished dimensions are no longer within it. :)

[Nissim Avrahami]

Yeap, it's a "Reaction wood"...you are lucky that it sprang "in" and not sprang "out", otherwise, the post title would be "Kick-back".:)

It happened to me ones, also with white oak and I used wedges to complete the cut...

niki

http://i208.photobucket.com/albums/bb151/matsukawa/Picture%20frame%20WIP/10.jpg


http://i208.photobucket.com/albums/bb151/matsukawa/Picture%20frame%20WIP/11.jpg


http://i208.photobucket.com/albums/bb151/matsukawa/Picture%20frame%20WIP/12.jpg


http://i208.photobucket.com/albums/bb151/matsukawa/Picture%20frame%20WIP/13.jpg

[Rod Sheridan]

Hi Jay, you are indeed cutting wood with significant internal stresses.

I suggest you use a bandsaw to rip the pieces over size, (no kick back danger) and let the wood sit for a couple of days. (It will change shape slightly during this time). Then you can edge joint it, and run it through the tablesaw, taking off only a small amount of material.

The wood may move again very slightly, however since you are only trimming a small amount off, it shouldn't be noticable.

Regards, Rod.

[Leo Zick]

im no expert, and in this case its probably the wood more than the saw. (could the wood still be too green?). i do remember reading though, that some table saws specifically recommend a thin kerf blade only. perhaps this is the reason?

[Jay Basen]

Thanks to all that replied. The pictures uploaded by Nissim are exactly what is happening to me. I'm wondering if the extra heat generated because my blade had pitch built up was causing the wood to be reactive.

The suggestion of ripping first on a band saw and then doing a final rip on the table saw is a great one. When I was doing a final trim rip on some of the pieces I was working with that just cut away a very small amount, I had no problems. Thanks for this tip Rod!

My saw is a craftsman (same as steel city) cabinet saw and the splitter is inexpensive sheet metal though it does also integrate the blade guard. I haven't measured it but it does appear to be narrower than my blade. Any suggestions on a replacement that would fit this saw?

Fortunately, I'm done with the batch of wood that I was having the problem with. I'm going to a different supplier this afternoon to pick up some additional quarter sawn white oak. It will be interesting to see if the problem disappears.

Thanks again for everyone's help!!

Jay

[Nissim Avrahami]

Hi Jay

Before you go and waste money on a new splitter, I would like to show you the "Riving Knife Rules"....The Riving knife thickness *should* be less than the kerf thickness....I believe that the same rule applies to splitter...

Regards
niki

http://i208.photobucket.com/albums/bb151/matsukawa/RivingKnifeD.jpg

[Neal Clayton]

i would bet on the fence or table being out of alignment as well.

crank the blade all the way up and measure with some calipers on each end of the blade between the teeth and the miter slots too. if the table is cocked to the right it will pinch on the back half of the blade.

[Mark Singer]

White QS oak often has internal stress . As you cut it can bind the blade. The simple solution is to rip to 1/2 the board depth, then flip the board over and rip the other half. This relieves the stress almost completely. Don't change anything on the saw, it is just technique

[Jay Basen]

Thanks Mark. I have quite a bit of sawing to do tonight as I just picked up a supply of qs white oak that I need to cut into sixteen 2" x 20" pieces for quadraliner legs to a table. I'll give this a try.

Thanks again

Jay

[Jay Basen]

I just wanted to follow up on the thread. I cut all my qs oak tonight without any problems at all. A differrent lot of wood and no issues. My only other theory is that the pitch on the blade was causing excess heat that contributed to the reactivity of the wood. I'm not sure I'll ever know but thanks to all that contributed. If I run into the problem again I have several techniques to use to work around the problem.

Thanks again

Jay