BTW, if you did not know, Jeff passed of cancer. I have taken over his duties managing the shop at Tuckahoe.
No I did not. Sorry to hear that.
Not 100% sure but I think this is Albert's grave. The timeframe fits.
Albert J. Davis (1824-1901) - Find A Grave Memorial
This is his brother Andrew. He was also a machinist. He died in the Civil War.
Capt Andrew S. Davis (1833-1863) - Find A Grave Memorial
This is his brother Charles D.B. Davis. He had a foundry.
Charles D. B. Davis (1832-1892) - Find A Grave Memorial
Have not found out anything on J. Frank Davis