I searched the Lumberjocks.com woodworking web site to see if anyone else has made serving trays. I found where one gentleman had made a 4-partition walnut serving tray for his mother. You can see this blog using this link.
I took a screen shot of the guy's serving tray and imported it into Sketchup. He said the OD was 13 inches, so in Sketchup I scaled the image to get the 13 inch OD. I also measured the center hole diameter and the wall thickness.........and decided what I would use on my project.
I laid out my design first without the fillets. I decided to finish design 1/4 of the tray, then copy, paste, and rotate the other 3 pieces.
The kit I bought from Eagle America had 2 round bottom bit..........one with a 3/4" cutting diameter..........and one with a 1.25" cutting diameter. I try to keep designs as simple as possible, so on this project I want to use just the larger bit. So, I want my fillets to be a little larger than 1.25" diameter.......so I used 1-3/8" diameter.
Back when I started as an engineer in 1978 on the drafting table at Ford Tractor Company, I would have laid out the design without fillets as is shown above. I would have then drawn a vertical line (1-3/8 divided by = 11/16) to the left of vertical tray border. I would then take my compass set to a 11/16 radius and moved the compass up until I blended smoothly with the top circle.......and that created my center point for the compass.
In Sketchup, I did the same sort of thing. I created a circle with a 11/16 radius and made it a group. I created a temporary vertical line 11/16 to the left of the tray border.............then moved the circle group up until it blended smoothly to the outer circle. I then erased the un-needed objects......leaving a blend fillet. This is not perfect, but is pretty darn close.
I remember in high school geometry class using a compass to bisect an angle. I don't remember learning how to make a circle tangent to a line intersecting a circle??
I Googled it and found a Youtube video which explains how to make a circle tangent to a line and a circle. Instead of measuring up from the circle, I measured down and it works!!
I don't think this design quite looks right.............next I will show a thin layer of 1/4" thick maple on top, which I think looks better.
My planer's max width is 12.5 inches, and this design has a 13 inch OD.
However, on the Squirrel tray, I did not plane layer 1 or layer 2. I was very careful when I glued up each level, to get the best match I could. Worst case, I would use belt sander to remove any mismatch on this project.
For the 1/4" maple on top option, I could try the lower level being standard 3/4" thick walnut.
The Eagle American web site says to leave 1/2" thickness on bottom of tray. If I cut this to 1/4"............my tray compartment depth would be the 1/4" maple on top + 1/2 in the walnut, which would give 3/4" height. I don't know if this is too small compared to the 1 depth you get using two levels of 3/4" thick stock.
If I keep the 1.5 inch overall thickness and use 1/4" maple on top.........then my walnut needs to be 1.25" thick, which means 2 standard 3/4" thick pieces glued together and then planed down from 1.5 to 1.25.
Options to Ponder........