I thought I'd bump this old thread as I am getting ready to make my drawers with dominos.
I am torn if I want to have through tenons, so I am debating which size to go with.
My drawer sides and fronts are all 1/2" baltic birch. It seems like the way to assemble this is with the 4mm cutter and 4x20 tenon, with the plunge set at 20mm for both sides (since it really will only cut 10mm). This would not show a through tenon.
To get a through tenon, according to Festool with 1/2" material, they recommend the 4x20mm tenon, with the 15mm plunge setting (i assume I'd set the other 25mm for the through portion).
The 4mm tenon size seems a little small as a through tenon, so I debated using the 5mm size…although that seems a little large using the rule of 1/3.
What size tenons do folks use with 1/2" stock using a though tenon?