Table Saw Miter Cut "U" Shape

[John K Jordan]

Ah, I didn't know that was a thing.

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[Brian Tymchak]

Good idea. I will give that a try in the short term

Turns out my blade is .0004 off at 90 degrees and .0012 off at 45. After Christmas I will get to fixing this but need a faster solution for now and this might be it.

If you got the number of 0s right in your measurements, then I'd say that is pretty good accuracy and don't touch a thing. The problem is most likely in your sled. Do you have any play of the miter bar in the miter slot? Or another thing that comes to mind is that the sled might be sticking on the saw surface when you push it through the cut. Clean and wax both the sled bottom and saw surface, and wax the miter slot and bar.

[Andrew Seemann]

Good idea. I will give that a try in the short term

Turns out my blade is .0004 off at 90 degrees and .0012 off at 45. After Christmas I will get to fixing this but need a faster solution for now and this might be it.

if your blade is really within 4 ten thousandths of an inch and 12 ten thousandths, you won't get that better. That is well below the machining tolerance of the machine as a whole. Even 4 thousandths and 12 thousandths probably would not cause what you are describing. And even if they are off by that much, it won't cause the work to rotate, the angle would just be off, and not enough to notice.

The issue is with how the work is going past the blade. Either it is rotating slightly , or the blade isn't aligned with the miter slots, or you have too much slop in the miter slots relative to the jig. My old saw had that problem, the miter slots were so worn that they would be tight at the ends but sloppy in the middle.

[Mike Geig]

I've rebuild the sled with no slop at all and aligned with the blade. The blade is a little off from the miter slots (as indicated) but I agree that it shouldn't be causing as much of this motion. If nothing else, this has been a good learning exercise. Unfortunately, my wood has started to cup a little. I started this project with 8/4 hard maple. I brought it into my shop and let it set. Then I rough dimensioned it and again let it set (about 2 weeks). Then I dialed in the jointing and planing. I was hoping that it milling it is stages I would catch any warping. My shop isn't heated though and I live in Ohio, so I think the cold has caused more warping now which, even though I tuned up the sled, it introducing more slop into the cuts. It never ends

[Lee Schierer]

Any time your wood is not actively being worked it should be stacked so air gets equally to all surfaces. Never leave your wood on a surface where the air can't get to the faces. 2 weeks is not a long time for 8/4 wood to a acclimate.

[Thomas L Carpenter]

I've had something similar happen when I rush the cut. Slow and easy seemed to solve my problem.