You can see three sides clamped into place on the box.
The bottom of the box is plywood, but the sides are aromatic cedar. Aromatic cedar is relatively soft nice wood to work with, most of the time. The wood can be chippy and knots are especially hard and will deflect drill bits or saw blades if you are not vigilant however. The fourth side chipped while I was fitting it to the box. I was able to glue three sides in place but I had to glue the chipped board together before I could glue it in place.
I decided on a sliding lid for this paint box and so had to cut 1/8 inch dadoes in three sides. In table saw days I would have ripped those slots in minutes. Without the table saw I opted for another method, that worked fine and was quieter.
I laid out the lines for the dado and used my home made marking knife to cut the lines into the wood. I found that I could only hold the ruler perfectly straight and still by clamping it into place. I scored each line into the cedar multiple times and then cut down the lines with my dove tail saw. This was one of those "OH" "DUH" experiences. I'd made three marking knives while on a blacksmithing course a few year ago, and not used any of them much. If you are going to cut your material with a power saw, scoring the wood isn't really needed. Those of you that are smarter than I am, (that's everyone right now) know that when you score a line with a marking knife the hand saw blade settles into the cut much easier and faster and your cut gets better automatically. DUH. So I made the six cuts, easily and accurately and used a narrow chisel to clear out the little bit of wood that remained. Chisels are generally 1/4" and wider. My 1/8" inch chisel is a souvenir that I bought at a tool store in Berlin, Germany on a trip in 2010.
How did I know when to stop cutting you ask. I made a depth gauge by marking 3/8" on a putty knife blade and used that to check how deeply I had cut into the wood. I could have also marked the saw plate but decided that was a habit I didn't what to start. Thinking about it now, I could have put painters tape on the saw plate to mark the depth!!! I'll get better at these short cut and tricks the more I saw by hand.
These are the three marking knives that I made 2012. I brought them home, fitted handles (poorly) and sharpened them (sort of). It is clearly time to treat these tools with the respect to which they are entitled. That will be my ongoing project. I have good saws, and now I know how to make quality cuts, duh.