Introduction: Penny Whistle From an Old Mop

Take an old mop handle (or really any scrap piece of metal tubing) and turn it into an heirloom quality penny whistle... for less than a penny!

The first question you need to answer, though, is "why?"

I purchased a commercial tin whistle from Ebay a few months back for only around $10. Sure, I could have made $10 faster than I made this whistle, but I still believe there are a few significant reasons to do it.

1) Durability - The commercial tin whistle that I purchased now has a 30 degree bend in the middle after my son used it as a drum stick (at 1.5 years old, drums is really the only instrument he seems to understand). He has also used my DIY whistle as a drum stick. It remains straight as an arrow. Or at least as straight as an old mop handle.

2) Customization - Yes, tin whistles in the key of D are a dime a dozen (not really, see above). That being said, my creation is in the key of A, which is much less common and therefore much more expensive than the typical Key of D whistle. Also, I feel totally confident to fiddle around with this whistle till it sounds just the way I want at just the right amount of breath.

3) Price - This was basically covered already, but yes this whistle really probably cost me less than a penny to make. I got both the mop handle for the bore and the block of wood for free and really only spent money on the super glue. It will of course cost you more if you have to buy any tools for the build. Even then, I think you could do it for less than $20.

4) Fun - Playing an instrument that you built is an amazing thrill! Your heart will (or at least might) leap the first time you blow your first note on the whistle as it takes shape in your hands! Also, you will never understand your instruments quite so well as when you make them yourself.

Happy Building!



- Mop handle or any scrap of metal tubing - Ideas of things that are often discarded: broom handles, copper pipe, aluminum crutches... Get creative!

- Small section of hard wood (this does not have to be hard wood, but that is what I used and I can't speak to how a softer wood affects the sound.

- Super Glue


- Tape Measure

- Sharpie Pen or Pencil

- Hack saw

- Sand paper (various grits)

- Files of various sizes

- Drill Motor (with Various Sized Bits)

- Hammer

- Something to hold the work piece (bench vise or clamps)

- Plumbing Pipe Cutter (optional)

- Digital calipers (optional, you can get by with the tape)

- Punch (could just use a nail or drill carefully)

Step 1: Understand How a Whistle Works

Before you start building, it is helpful to understand how the whistle you are making will work. How does a whistle actually make sound?

I find it helpful to begin thinking of the wing of an aircraft. If you look at a bisection of a wing and think of the air moving above and below the wing, you see that the wing is aerodynamic and that the air attaches at the front of the wing and remains laminar until it detaches at the back. This reduces the turbulence of the airflow around the wing which creates less drag.

The whistle is kind of like a bad wing. If you blow into a regular pipe you won't hear a sound much different than when you blow into the air. There is low pressure and low turbulence in the unimpeded airflow through the tube. In a whistle, you blow into the mouthpiece which is in large part blocked (by the hardwood block in our case). This creates a narrow channel for the air which increases the pressure. Pressure is mass divided by the volume. You are blowing the same mass of air into a constricted opening which increases the pressure. The block also directs the air to the blade of the mouthpiece.

The blade is basically a really inefficient wing. The air that flows over the blade remains laminar and escapes the whistle without event. But the air that flows under the blade cannot stay laminar because the blade presents too sharp of an angle. As the air detaches from the blade, it creates great turbulence. That turbulence then creates vibrations all over the spectrum of audible noise. However, the bore of the whistle is resonant at a particular frequency.

As the air continues down the bore of the whistle, the resonant frequency is amplified making that the primary frequency that you hear when you play your whistle. As you cover and uncover the holes of your whistle, you are changing the size of the resonating chamber and are thus changing the primary frequency. By placing and sizing the holes carefully you are able to tune the whistle. This is how you are able to consistently play specific notes.

Step 2: Determine and Cut the Tube to Length

You can approach this step two ways. If you are not trying to create a whistle in a specific key, you can just cut the tube to a length that you like. The longer the pipe, the lower your bell note will be (that is the note that sounds when all of the holes are covered up). The lower the bell note, the lower the key of the whistle.

If you have a specific key that you are shooting for, go to the whistle calculator at and plug in the dimensions of your pipe. that should give you an idea of how long you need it to be. The place that the calculator says to drill the hole for the highest pitch note has to be somewhere on your whistle.

My goal for this whistle was A major and I cut my piece to 16 inches. Remember, you can always go shorter when it comes time to tune, but you can't go longer (at least not easily).

If you are using a hacksaw, I recommend you make the mark at the length you want. Then using a straight-edged piece of paper wrapped around the pipe, circumscribe all the way around where you want to cut. Then find a way to secure the piece (I used a bench vise) and take a few strokes and then rotate. Take a few strokes and then rotate. Take a few strokes and then rotate. All the way around the pipe and until you are through. This will help to guarantee that you are cutting straight.

This part (and tuning later) is much easier if you have the plumbing pipe cutter.

Step 3: Prepare the Tube for the Block

You could use a dowel for the block and then you would not have to do this step. However, I find that I get a louder and more consistent tone if the mouth piece is squared off. This step is actually really easy.

Take three scrap pieces of wood of the same thickness and make sure that they all have at least one straight edge (not super critical, but sorta straight). Secure the three together so that the middle piece sits below the outside pieces making a channel down the middle (see the picture). The pipe should be just a bit bigger than the channel that these three pieces form.

Mark the pipe about an inch and a half back from the end. That is how long the mouth piece will be. In the picture, I also have already marked where the window will be, but I suggest holding off on that.

Secure your jig in a vise (or clamp on the ground) and set the end of your pipe over the jig at the 1.5 inch mark that you made. Begin to hit the pipe gently to discover how much force is required to deform the metal. You want the pipe to bend, but you don't want to crush it with a single blow and the harder you hit, the more marks you have to sand out later. Once the metal begins to deform, rotate the pipe 90 degrees and take another couple of swings. Continue to rotate the pipe 90 degrees every couple of swings and force the pipe into the jig. The jig acts as an anvil on the bottom and the two side. If you just hit the pipe on the back of the vise, it would deform into an oblong shape and not a square. Now you have a 1.5 inch square tube on the end of your pipe.

Step 4: Prepare the Block

First measure the inside dimensions of your square tube. It should be square, but if it is far off, take it back to the jig for corrections.

Assuming that you were able to square it up, take the measurement and mark that onto a small block of hard wood that is close to the same dimensions as your square tube. However, it should be a few inches longer than 1.5 inches, so you have something to pull it out of the whistle with.

I used my calipers to get the inside dimension and then ran the jaw of the caliper down the side of the block to get the measurement scribed onto the wood. You can use a saw to cut close to the line and then finish it off with sandpaper on a flat surface.

Once you have the block close, you can bevel the very end of the block with a knife so that it just fits into the tube. Then use a hammer to set the block into the tube (See pictures). If the block is not far oversized, the tube will actually shave off those last few thousands of an inch and it can help straighten out and weeble wobble in the squareness of the tube. It is a symbiotic relationship. Beautiful!

Once the block is the right dimension, take it back to the sand paper and remove another 1/16th of and inch. this will be what forms the airway of the mouthpiece.

Step 5: Cut the Window

The window is the small gap between the end of the block and the blade. Really when you are cutting the window, you are forming the blade of the mouthpiece at the same time.

From the end of the mouth piece (with the block of wood removed), measure one inch up. Make a mark straight across with pencil or marker.

Use the hacksaw to cut on this line just deep enough that you are completely through one side (you should be able to see into the tube through the length of the cut).

Then take a file or sandpaper wrapped around a block of wood and begin to remove metal at a 45 degree angle away from the end of the mouthpiece (the angle should slope up toward the bore of the whistle). Continue to remove metal until the gap between the original edge of the cut and the edge of the blade (i.e. slope) that you just formed is about 1/8th of an inch.

Make sure to clean up any burrs at this point. You don't want anything sharp for the next step.

Step 6: Insert and Secure the Block

Insert the block so that the front of the block lines up with the edge of the window. At this point, you should be able to blow into the airway and make a tone (although it is probably not the tone you are after). If you are able to get a tone, you should be ready to secure the block.

For this, I inserted a bit of wood (could use a Popsicle stick) though the window to hold the block in place. then I dripped super glue along the edge of the wood. The capillary effect will disperse the glue between the wood and the metal tube. Leave this to set.

After the glue has set, you can cut off the excess of block that is sticking out the mouth piece and use the hacksaw to shape the mouth piece (if desired, this will not effect the tone).

Step 7: Tune Your Whistle

At this point you are ready to tune your whistle. I used a tuning app on my phone, but basically any tuner (or a piano) will work. Blow into your whistle and determine what note sounds. This is the bell note and is the lowest note your whistle will play. If the note is too low, cut away small amounts off the end of the bore until you are playing the desired note. If the note is too high... I guess start over or adjust your expectations.

Once you have the whistle playing the right note, you need to calculate where to drill the six holes that will make your whistle into a proper penny whistle. There are many free calculators available online for this part, but I have had the best luck with this one:

I have not found that it is essential to get exact measurements, but only close. If you take your time with the next step, you should be able to get good results if the numbers you enter are close. Play with the size of the finger holes on the calculator if they are too close or too far apart for your hands.

I marked a line down the center of the whistle with a pencil and then use the tape measure to mark where the center of the holes needed to be. I then used a punch to make a dimple in the metal to set my drill bit in. I started at the smallest drill bit I had and then moved up through the bits, playing the whistle after each hole to make sure that I was inching up on the right note. This is a slow way to do it, but it helps to make up for any error in measuring.

Step 8: Clean Up and Play Away!

Once you have your whistle tuned, you want to go over it with some sand paper to get rid of any burrs or sharp edges. After that, you are ready to play!

Have fun with it!

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