You could try the 5 sided cut test. I do this a few times a year to re-certify my sleds. For my miter gauge I just clamp the miter bar in the vise with the head hanging toward the floor and use my Wixey to confirm 90* but the 5 sided method can certify gauges as well.
Example here, scroll down to the section just above "Calibrating Crosscut Fixtures/Sliding Tables" and click the word next by the picture:
This method uses the actual cut as opposed to a measuring tool. No matter how good your triangle or square may be, as you hold it up against a surface and try to sight long the blade, too many elements come into play to make it easy to get into the thousandths for accuracy. By using the cut result to test, adjust, test, adjust; you end up with the actual result from your saw cut.
Last edited by glenn bradley; 11-05-2008 at 01:43 PM.
Any sufficiently advanced technology is indistinguishable from magic.
- Arthur C. Clarke