I donate woodworking items to a non-profit group that sells them as fund raisers.
For a future project, I could make 4 dowel whistles with a leather cord connecting them all together.
I have made various wood whistles using 1/4, 3/8, and 1/2" diameter holes.
Using data from previous projects, I made up the spreadsheet shown above.
I made 4 whistles from 5/8" birch dowel, with 1/4" diameter holes.
I had only made 1 whistle with a 1/4 hole, so I was surprised at the results. Only the shortest depth whistle would work!! I could not get the other 3 depths to work at all !!
I decided to keep the shortest whistle, then drill the other 3 whistles with 3/8" diameter and reeds...........to the same depths.
I got all 3 of these whistles to work ok.
If I made new sets of 4 whistles, then.....
-use 3/4" dowel with 3/8" diameter holes
-or 3/4" dowel with 1/2" diameter holes
I like the 1/2" diameter holes on the square 4-tone train whistle, so maybe go with 1/2" versus 3/8" holes.
My grand-daughter liked the 2nd longest whistle using 5/8" dowel and 1/4" dia reed, 3.0 inches deep.