At least on one of those appearances he was with Norm of This Old House and The New Yankee Workshop. I remember them building window screen frames.
Amazingly, he was able to tell a saw from a hammer, but he couldn't quite guide the circular saw straight. Letterman complained about Vila plugging Sears so much.
They say Vila treats the craftsmen on his show badly to make himself look smarter. He'll ask one of the craftsmen on camera what he's doing, and the person will explain it. Then Vila will stop the camera and ask the question again, this time rephrasing it so it contains the answer the person just gave him, and all the craftsman can do is reply by saying, "That's right, Bob."