On July 12, 1938, Sarah and John Hammell celebrated their 55th wedding anniversary. It seems likely this portrait was taken on the occasion of a wedding anniversary, and maybe the 55th, but I don’t have a specific year for it.

If it was not taken for their 55th, it was close enough that we can pretend it was. ;–) In any event, it is really a very nice portrait of them.
A notice of their anniversary appeared in the Albany Democrat-Herald a few days after. I imagine the spelling of “Hammel” with one “L” was Floyd’s (Uncle Jack’s) doing, since he preferred that spelling. I assume the reference to “F. H. Hammel” (instead of “F. J.”) was a typo.
It is certainly notable that Great-Grandpa Hammell, at age 78, was still involved with construction (in this case, the “city swimming pool,” which refers to Swanson Pool, more recently rebuilt as a water park named “Cool Pool”). It isn’t clear (to me, at least) precisely what “in charge of” means here. Was he the general contractor for the project? He was involved with city government, too, so was he “in charge of” the pool project for the city? (If you know more about this, please provide enlightenment in the comments.)
Their 55th would prove to be their last major anniversary. Sarah passed away three years later, in 1941. By all external indications, their relationship was a good one—especially good for John, I think. Although he lived fourteen years after Sarah passed away, there is a sense in which his life was not as good after she was gone.
It is perhaps worth mentioning in this context that there was an earlier post about Sarah and John’s wedding in Coshocton County, Ohio. (Incidentally, the name of the community where Sarah’s parents lived at the time, and where the wedding was held, was New Guilford, not “Gilford” as the newspaper has it above.)