Question for the woodworkers - filling gaps in wooden table top

[muddy42]

No, just camp and saw the joint. Side will be parralel so can be glued. This is how big beams get patched is situ, they just run a handsaw between the old and new piece to get the faces parralel and then glue.
After sawing take the top planks apart and reglue with a somewhat filling glue. If needed use a new spline.
All this can be dine in the room, if you don't mind a little sawdust or use a vac on the saw.

I can't advice how to attach to the base, because I have no info on how this is made, but this is mostly not very difficult to do in a way the top can move.

Ah I follow you. I use that trick to get wooden patches parallel. It would take a few passes because in some places the gaps are wider than a saw kerf. The top attached to the base with pocket hole screws from underneath.

 

[Emilio]

Ah I follow you. I use that trick to get wooden patches parallel. It would take a few passes because in some places the gaps are wider than a saw kerf. The top attached to the base with pocket hole screws from underneath.

I would first loosen the top, clamp it to minimise gaps, put some slats underneath to prevent sawing into the base and then saw allong a ruler.
If you have a traditional style base, you should fasten it in a fashion as shown in the picture below, that way it can move as a whole without splitting.

 

[Flash G 74]

Hello, What is the timber of your table ??