To recap some information posted previously, American Fork & Hoe owned the True Temper brand before they bought Kelly Axe in 1930. There were TRUE TEMPER Kelly Perfect axes
advertised in the 1930s. There were some TRUE TEMPER axes (with
no mention of Kelly)
advertised in the early 1940s.
YesteryearsTools says,
"In order to facilitate the acceptance of the [1930] company changeover, the American Fork & Hoe Co. operated their axe division under the name of the Kelly Axe & Tool Works. A slight difference initially, but gradually many the brand names were combined with the name True Temper. Others were discontinued or shelved. By 1949 the entire American Fork & Hoe Co. became known as True Temper and they reincorporated under that name. "
Perhaps this "True Temper Lippincott" was made during the early 1940s (along with the well-documented axes being sold as True Temper during the early 1940s without reference to Kelly, with similar-looking stampings).
When did they start stamping "Kelly Works" on axes? Perhaps they started stamping "Kelly Works" after the corporation name changed to "True Temper" in 1949. This
journal from 1953 refers to the "True Temper Corporation, Kelly Works, Charleston, W. Va.", and states that
"The Kelly Works is the largest axe and hoe factory in the world."
So, my speculation would be that the "True Temper Lippencott" axe (with no mention of Kelly Works) was from the early 1940s or earlier (but no earlier than 1930).