Tools, Sharpening and Power Machinery - Sled for my table saw

I built a table saw sled for cutting large sheets of 3/4 plywood. My design is fine except for the fact that I cannot get the guide/fence to be exactly 90 degrees from the saw blade. I've tried resting my right angle against the blade and against the saw cut. I've remeasured and repositioned the fence many many times and right now it is only a hair off, but it is enough to show on a 36" cut. I've decided that it's good enough and I'm proceeding with the rest of the construction (I'm building cabinets), but I thought that I'd ask.

Is there anyway to get a very accurate 90 degree angle on my sled fence?

Thanks.

George Kopf

George,

If you have built it as pictured and use the grooves in the table for the slide, you must first make sure the blade is perfectly parallel to the grooves.
This adjustment is made by loosening and adjusting the mandrel.
Once the blade is properly set then the fence can be set for a perfect cut.

<img src="http://www.imaging.robarts.ca/~amulder/wood/j.sled2/sled2-sm.jpg">
Image credit: imaging.roberts.ca

I actually discovered my problem. The board that I was using for my fence was a hair thicker down on the end away from the blade. That meant that when I squared the blade to the fence using my 24" right angle, I got a perfect 90 degrees and any boards at that length, or shorter, would be perfect. But when I cut a large sheet (36") they would be a hair off. I thought that I had squared the board that I used as the fence but in actuallity I had created a little lip. I squared the fence, re-aligned it and all is well in my shop.

Thanks for the help.

George Kopf

Nice sled, Greg