I've covered building the spools in another Instructable, so here I will focus on the rack that I designed for tabletop use.
-2 10"x24"x1/2" boards (I used some scrap plywood lying around; I can't help but think that this would've looked better in oak)
-1 10"x22"x1/2" board (to act as a shelf)
-1 2"x22"x1/2" piece of lumber (I used pine; this is a horizontal strut for stability)
-1 1"x28" wooden dowel (we had an old broom handle laying around that cleaned up nicely)
-Bandsaw (if you have a thin enough blade, you might be able to get away with using a handheld scroll saw)
-Belt Sander (you could certainly hand sand these, if you have no life and eternal patience)
-90 degree angle clamps (these are a lifesaver. I used the makerspace's, but I now plan on getting my own)
-Powerdrill, drill bits, screws.
-Compass (the circle-drawing kind, not the superstitious "magnetic" ones)
-A 1 1/4" hole-saw (not essential...it just made things a little easier)
Step 1: Layout and Planning
To that end I decided that I wanted to taper the top of the rack to a rounded curve. This was very easy to do.
First, I decided on the height that the middle shelf would need to be at. Since my spools were 8" in diameter, it was easiest to just divide the sides in half, giving me 12" on either side of the shelf (minus 1/2" for the shelf's thickness).
I drew my line midway to represent where the shelf would go, then split the sides vertically, right down the middle. I bisected the top half of the side and drew a circle with my compass to represent the spot where the dowel would rest.
For the top point, I used the middle, vertical line and decided on a 2" diameter curve, easily achieved with a compass. I connected the edges of the curve to the ends of the middle shelf line, thus giving me a guide for my taper.
I wanted a slot so that you could slide the fully loaded dowel into place without having to remove the spools first.
I pretty much just eyeballed it. I used a French Curve to keep the slot the same shape throughout.
Important note: Make sure that, since the dowel is 1" in diameter, the end of the slot in the side is big enough to accommodate this. In my first sketch, I just drew the lines from the edges of the middle circle right to the outside and found that as it curves, the slot narrows significantly.
The pencil didn't show up too well in the photograph, so I've used Inkscape to sketch the lines in.