Table Saw Blade Problems

[Clark Harbaugh]

I just ran a few test cuts on a recently sharpened 24t thin kerf Freud. The bottom 1/4" or so shows a bunch of radial saw marks, however the top part of the piece looks fine. I just went back through the saw setup, and the blade is parallel to the miter slots and the fence. Any ideas why this is happening? Hopefully the pic shows what I'm trying to explain.


20170907_192950.jpg

[Tim Janssen]

It looks like those marks are being made by the back of the blade. That might be a clue to the problem. Is the fence parallel to the blade?
Worth checking. Could also be that the wood is twisting as it is being cut.

Tim

Just read your post again and you stated that the fence is parallel to the blade.

[Paul F Franklin]

Try slowing your feed rate down. If that improves it, your blade may be deflecting.

[Clark Harbaugh]

I agree it looks like the back of the blade. Maybe I'll check again on the alignment.

[andy bessette]

I would try a better blade. Why thin kerf?

[Lee Schierer]

I agree it looks like the back of the blade. Maybe I'll check again on the alignment.

I was going to suggest checking the alignment of the blade to the miter slot and then the fence to the miter slot. Those marks are typical for an alignment problem.

[glenn bradley]

As others have said, feed path deviation. If it is consistent on all cuts I would look to alignment. Since it is happening out of true (lower portion of material effected but not the higher portion of the field) I would confirm the two faces being used as your reference surfaces (the side facing the table and the side facing the fence) are true to 90 degrees. The fence also needs to be reliably perpendicular to the table as well as aligned with the blade. If it happens on some material and not on others I would lean toward wood movement during the cut.

[Clark Harbaugh]

Looks like it is a blade problem. Not sure why I didn't think about this yesterday, but just swapped in my old combo blade. No tooth marks on the bottom. Guess it is deflection/vibration. I never had that issue before having it sharpened. Guess I need to find a different source. Oh well, excuse to go buy a better blade!

[Doug Garson]

Maybe contact your blade sharpening service and explain your problem rather than right them off without giving them the chance to make it right. You could have the one blade in a thousand they mess up.

[Evan Stewart]

I had a similar situation with a thin kerf blade awhile ago. My theory was that the blade had warped slightly after milling a decent amount of hard maple that was binding the blade due to internal board stress. After double checking alignment of the fence the problem persisted but after switching to a regular kerf blade everything was fine. Since then I haven't put a thin kerf blade on my TS unless I'm making final dimension cuts.

[Lee Schierer]

If you need a smooth cutting rip blade take a look at the Freud Glue Line rip blade. It is a full kerf blade that cuts as well or better than a 24 tooth thin kerf on my Craftsman 1-1/2 Hp saw.

[Rich Engelhardt]

take a look at the Freud Glue Line rip blade.

+1 to that.
I did away with all thin kerf blades on my contractor saw and went over to full kerf.
I seldom, if ever, cut anything thicker than 1" so I really don't notice a lack of power - - matter of fact - - the added inertia of the heavier full kerf blade seems to help it go through 3/4" wood easier.

[Clark Harbaugh]

So, I put on a full kerf glue line rip from Freud. I now have radial.marks in both directions (indicating both front and back of blade) and consistently the full height. I had to step away, as I found myself in the proverbial 'forest for the trees' situation. Busted out the dial indicator to double check. The blade is <.001 with the back of the blade ever so slightly (maybe .0005) away from the right miter. Don't think I'm going to improve that. I did notice that the face on my fence is wavy, so possibly that is my problem. To be on the safe side, I'm going to build a new face to test with. Never really like the plastic face on the Shop Fox. Otherwise, I'm out of guesses.

[Peter Christensen]

It's a long shot but here is another possibility. The bearings may be starting to go. You have the dial indictor so take the blade off and put the indicator tip on the end of the shaft and try to move it from side to side with a board or pry bar. After that put it on the side of the shaft and see if it moves when force is applied. If there is no detectible play then your issue is alignment based and if there is you need new bearings.

[Rich Engelhardt]

So, I put on a full kerf glue line rip from Freud. I now have radial.marks in both directions (indicating both front and back of blade) and consistently the full height.

OK - that's not altogether bad news.
When you changed the blade, you also changed the problem.
I suggest returning to the original blade, retest it to make sure only one set of marks is there, then make another change and test it again.