Bill Tindall, E.Tn.
The top is round. The support is a cross. How to fasten top to cross?
One long arm of the cross could be installed parallel to the long grain of the top. It seems like it might look better this way. The screws might locate in the center top joint-probably not the best. But there would be no expansion/contraction issues with these screws. However, I would have to allow for ample changes along the other arm which would be perpendicular to the long grain.
Arms could be installed 45 degrees to the long grain. Surprisingly it looked ok in this orientation. All the screws would have expansion/contraction to deal with but it would be minimized by 45 degree orientation. Unsure if potential cupping of top would be better or worse restrained by this orientation.
No doubt someone in 1720 figured out empirically what worked best. But I have never looked under a round top to see what was done.
Opinions? BTW the cabinets in the back are ash and finished with the same product as the table. They darkened that much over time!