How can I make these splines?

[glenn bradley]

I agree that the alignment is not a big deal as long as you have a consistent reference surface.

Miter-Key-Jig-in-use 006.jpg

These little carriers for the tablesaw used with a flat top grind blade work very well. Spacers can be used to create the extra width of the initial slot and the narrow secondary slot.

We all tend to approach things based on our experience and out successes. Creating the stock in advance can certainly be done. I just think it is overly involved for the desired outcome. Now, if you are going to make a dozen of these, I might change my approach.

[Dave Zellers]

No one has mentioned that the lid handle matches the splines on this box. (minus the back band)

I think the splines were fabricated in advance and only one cut was made.

As Peter said.