I wanted to make sure that my Table Saw blade was perfectly aligned to the table saw miter slot. I used an old Dial Indicator that I had, but you can get a cheapy from Amazon for $11.99.

I made it adjustable so that it can be used on a variety of table saws with a ¾" miter slot.

I used a ¼-20 cap bolt to lock the indicator to the holder, and a ¼-20 threaded stud with a thumb nut for the slide mechanism.