The screw on the tilting mechanism of my Home Casual Pagoda Patio Umbrella came out. There is a spring and a cam that go inside. I cannot figure out how to reassemble the unit. Can anyone tell me?

There is a small hole in the pole where the spring goes and a pin on the tilt button that goes into the spring. The trick is to move the top pole slightly away from the bottom pole so the push-button & spring will slide over a stop that is in the bottom pole. You have to remove the fabric on a few of the vanes to see in where the two poles meet. Once the push button is in and the top & bottom poles are aligned, insert the screw and tighten with an allen wrench. Tilt works like new again.

Where can I get a tilt screw?

A good Local Hardware or Lowe's have special screws. Or if you kept the papers from the Umbrella, contact the manufacturer.