Jim Torrey, son of Orin and Claire, was the oldest grandchild of Avice, born April 17, 1933. 

The youngest of grandkids is Kathy Garrity, born in 1956...a 23-year generation.

Of the great grandchildren, Gary Blanchard (son of Jayne and Wayne) was the first-born on February 2, 1956. 

That generation lasted until the birth of Holly Garrity in 1985, 29 years later.