Using the traditional angle checking tools, such as drafting triangles and squares, still is a good place to start when building tablesaw sleds, especially miter sleds.
I don’t trust miter guages to stay on angle throughout a whole job. A picture frame, for example, has 8 miter cuts and just a small bump on a common miter guage can cause it to lose its setting between cuts. So I rely on fixed, shop made miter sleds. But making sure they’re exactly at the desired angle is critical.
So here’s a video I made to show how I do it. The sled I used for the video is one-tenth of a degree offf.
I got the idea when I saw another woodworker show how he sets his adjustable miter guage. I use a Wixey Digital Angle Guage to do it.
Here;s the link to my YouTube video:
Next time I want to make a short video that shows my method for checking the table saw fo accuracy.
-- Will trade wife's yarn for tools.