Underbench cabinet: 4. Dados
Derek Cohen (in Perth, Australia)
The case is a dry fit. Above the case is the outlay of the drawer blades for the drawers. Inside the case is the template (story stick) made to mark out the dados. The dados will be 12mm wide and 6mm deep ...
The template is alternated for each side, which ensures that they are marked at exactly the same position ..
The knife lines are deepened and undercut with a chisel to create a wall for a saw ..
A straight edge is clamped along the knife line, and a kerf is created with an azebiki saw ...
The waste can then be removed with a router plane ...
Why do it this way, and not use a power router or tablesaw? I believe that I can be more precise with hand tools. This includes the positioning and fine tuning of the dados.
The router plane's depth stop is set to 5mm, and this is reached incrementally ...
The final 1mm cut (to a depth of 6mm) is made by a smaller router plane ..
The reason for this is that, as with a smoother, which follows the undulations of a panel and removes the least about of material, so this small router plane will create an even depth.
The depth is checked ...
Any waste in the corners is removed with a side rebate plane (this is one from Veritas). be careful not to remove waste from the upper edge as this will change the position of the dado. The side rebate plane is the only plane which can plane along the inside edge of a dado or groove. It is used to increase the width of the dado - but if doing this, only remove waste from the upper edge side of the dado.
Test the fit as you go ...
Once done ...
... the surfaces are sanded to 240 grit. This is an original (!) Festool sander, when it was still "Festo"! I have had this about 25 years. Heavy, but works well for this task.
A final test for the accuracy is to align the sides ...
... and then run a drawer blade across both dados ...
Time to glue up 
Regards from Perth
Derek