I am trying to track down the name of a movie I saw in grade school. I saw the movie in the late 1970s on a reel to reel film. It was in color so probably made late 60s to early 70s.

The Film was about a father and a son building a bridge in colonial America. They had made a deal with a merchant to have the bridge open by the next time he came through. It was all about the construction of this bridge with wooden pegs, that they had to use metal nails at the end to finish on time.

Also the son make a glass window for his family cabin by cutting the bottoms out of round glass bottles.

Thats all I can remember. I have been looking for this movie for 30 years.