A gentleman who recently took my Basic Woodworking class told me about the Wixey digital angle gauge, which he had just purchased. I wasn't familiar with it, so he brought it in to show me how it worked. It didn't take me long to understand the importance of this device, so I bought one immediately.
This thing is amazing!
I put it down on my tablesaw, and zeroed it out, so it read absolute 0.
There are three magnets on the bottom of it, so I cranked my blade up all the way and attached the Wixey to it. Here you can see, it's reading 90 degrees,
which means my blade is perfectly adjusted. Since the cube is accurate to a tenth of a degree, you can micro adjust your blade to whatever angle you desire. I don't care how careful you are with a square, you'll never get the sort of accuracy like you get with this jewel.
Next stop - my jointer. Here, I placed the Wixey on the table, and zeroed it out again.
The I flipped it over to the fence, and checked the squareness of it, in relationship to the table. Ninety degrees, baby... that's what I'm talking about.
There are a lot of places that sell the Wixey, but I bought my Wixey here, and got a great deal.
On top of that, I bought a digital protractor, which works much the same way. It's perfect for adjusting my miter gauge. I'll try to get some photos of that, too. Stay tuned!.