Attaching a solid top to a solid carcass top?

[Brian Penning]

Recommendations? Screw? Screw and glue?
The front edge can't have any gaps between the 2 tops.
Thanks in advance for any and all replies.

[Tony Bilello]

Use Z clips. They fit into a dado slot on the carcass and screw to the underside of the top. They basically slide back and forth in the slot as the top expands and contracts.
The front edge cab be permanentlt screwed in place so all movement will be from the non-moving front edge toward the rear.

[Brian Penning]

Use Z clips. They fit into a dado slot on the carcass and screw to the underside of the top. They basically slide back and forth in the slot as the top expands and contracts.
The front edge cab be permanentlt screwed in place so all movement will be from the non-moving front edge toward the rear.

Not sure if I explained it clear enough but basically we're talking about sandwiching 2 solid layers of wood.
Your solution is for when there's only the solid top to contend with.

[Frank Drew]

Same wood, same grain direction, you could use screws. I probably wouldn't glue the two boards even given same wood/same grain orientation, just in case the outer board needs to be removed for a repair somewhere along the line.

If the grain directions differ, or if the wood species are quite different with probable differing expansion/contraction potentials, I'd screw tightly at the front and slot screw in the middle and back.

[Jamie Buxton]

If the grain is in the same direction, why not just glue the two pieces together? Where you can use clamps to squeeze them together, use them. Elsewhere, use screws from the underside to clamp until the glue cures. Then you can leave them or remove them.