Ultra-accurate table saw tune-up tip

here is the straightedge lined up on the blade

Table saw tune ups are necessary and annoying.  And for me, I've never really gotten my table saw "perfectly" tuned.  I've always had the nagging suspicion that using the blade as a reference was insufficient: with a 10" table saw blade, the distance between the reference teeth is a mere 5" or so.  That's not a lot of distance to magnify any deviation from square. 

But  this week I had a bright idea: I used my machinist's straightedge to lengthen the reference surface to a whopping 24".  By laying the bar flat on the table and resting one edge against two opposing teeth on the blade, I essentially increased my precision roughly 5-fold.

Check out these pics:

and there's the long leg of my good square against the edge: it's a little off.  how far off?

That far off!  That's around 1/64" of an inch over 24"  Small, but enough to confuse me when I'm sneaking up on the joinery.

after tapping the crosscut fence with a clamp, I'm now dead on.

how about a closeup?  that smaller scale is measuring how far the square is from the straightedge, and it's graduated in 1/64" :)

I made sure to align the straightedge with two of the same type of tooth on my blade. The chippers are centered on the blade.

These photos were taken with the iPhone 4.  The Closeups were taken on the iPhone using a free magnifying glass app.  Awesome!