I don''t know how to post photos, and couldn't come up with anything by searching. Any help is appreciated.
These are some calls from recent time in the garage.
As for the sprig whistle, I turn the barrel to .75-.80 inches and turn the lip at the mouthpiece end, and then the lanyard groove. The overall length is 4". The bore is .5" and the two holes are approx. 13/8 and 2.5" from the mouthpiece end. The bore should extend only 1/16" past the second hole. The holes are 1/4" or just smaller.
The wooden plug for the whistle is given a flat spot on the top for
the airway and glued in. The plug just shows itself at the edge of the first hole.
When you blow it, you cover the further hole from the mouthpiece to get your pintail sounds (rolling your tongue), and the teal, widgeon and drake mallard sounds are all made with both holes open.
The older Iverson whistles had one hole and really only made pintail pitch sounds, but the two holer is much better.
Hope this helps.
Pete