Another tongue & groove question

[dennis thompson]

I followed your advice & cut the tongues & groves using a dado & it's worked fine so far. When I attach them to the welsh dresser should the tongues be glued to the grooves? or just attached at the ends with brads?
Thanks
Dennis

[Peter Quinn]

Just brads and a little gap between boards, maybe .020" per joint? Butting them tight and gluing them together doesn't much allow for wood movement and makes them move as one monolith. Nails give a little, and a little gap makes them behave more like a floating panel. Usually boards for the back will involve some type of chamfer or bead which allows you to confuse the eye enough to disguise the necessary gap.