Well, since HE is supposed to be making it, I think it would depend on
his skill level with tools, and how much of this will actually be HIS
You could easily make a half lap grid that Tom is talking about by
simply offsetting a group of square cut rods determined by the size of
the inset squares.
You could cut the laps in the grid with a router table, a table saw
with dado blade, or even a router and suitable straight edge. Glue
the pieces together with a dot of glue in each joint, square it up with
a framing square, and let it sit.
If you were wise enough to cut all the pieces a little long, you can
now take it over to the table saw and size it perfectly.
If he is a young lad, his teachers and classmates may find it hard to
believe he has those abilities, but hey.... how long have Dads been
building the little pinewood derby cars "along" with their sons?