# Whistle design



## boroughdan (Jan 30, 2013)

Hello everyone. I need some help designing a simple whistle. Steve of Woodworking for Mere Mortals did a video about making a simple whistle/new years noisemaker. It is a dowel, let's say 1 inch with a hole drilled in center. a notch is carved out by cutting a 90 degree and 45 degree cut where the bottoms meet. Then a flattened dowel is inserted just right to make a sound. The first one I made turned out fine. Then I tried another later and it took a lot longer to get it to whistle. My plan is to make about 100 of these and sell for a couple of bucks at a flea market but I can't figure out the specifics in making it work. It has been luck on the ones that did work.

So can anyone explain what makes a simple whistle like this whistle. Like, how flat should the dowel that is inserted be, how deep does the notch need to be? I think i figure out the deeper the hole the deeper the sound but apart from that it must just be magic.


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## hairy (Sep 23, 2008)

I couldn't make a whistle to save my life, but Mary Anne can. http://lumberjocks.com/LateNightOwl/blog/15535


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## sras (Oct 31, 2009)

Hairy beat me to it - Mary Anne's blog is pretty good.


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## wormil (Nov 19, 2011)

I have not made that style but I've made PVC penny whistles. Once you get it the rest will be easy.

re: the dowel … the larger the windway the more breath it takes to blow the whistle and the louder it will be. Start with a small flat so the opening is maybe 2mm high then gradually increase it from there.

The notch does not need to be very deep, just enough so the ramp catches the rush of air.

The shorter the whistle, the higher pitched (shriller).


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## donjohn24 (Oct 15, 2010)

I think i figure out the deeper the hole the deeper the sound but apart from that it must just be magic.

As I understand it . . . . .

Blowing air across the sharp edge initially causes it to fill up the hole in the body, until the pressure rises so much that no more can get in - then the blown air deflects OUTSIDE the body, and sucks out some of the air inside as it does so (the Venturi effect - as employed in spray guns for example)

When the pressure inside the body drops sufficiently, the air can be deflected inside once again, and the whole cycle repeats.

The time it takes for a cycle obviously depends on the volume of the hole in the body, therefore, so does the pitch of the note made by the process.

For a successful whistle - or organ pipe - the flat on the dowel has to direct the air at the sharp edge, in a pretty thin stream.

In the organ pipes I made for my busker organs http://www.donjohnson24.co.uk/banjo.html the gap is made using cereal packet cardboard, which at 0.5mm is just about right. (The red bit in the diagram below)










Moving the stopper adjusts the pitch. The shape of the pipe affects the 'quality' of the sound - and so does the material used.


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## Wildwood (Jul 22, 2012)

I made a ton of this style whistle without band for kerchief.

http://www.e-scoutcraft.com/wood_carving/whistle.html

I varied diameter and length upon wood had laying around.


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## wormil (Nov 19, 2011)

All my whistles were drilled straight through.

The tricky part is getting the dowel to the right depth, get it wrong and you'll get little if any sound. I start with it extra long and flush with the straight part of the notch then move it in and out as necessary. If the flat on your dowel isn't perfectly straight, face it so that it ramps up toward the notch.


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