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This article was published in the November 2016 edition of More Woodturning
Warbling Whistle as 5 page pdf Whistle Jigs
Warbling Whistle
Design Inspiration
One of the variations I considered (but didn’t complete)
when designing the Whistling top (published in the August 2016 issue of More
Woodturning) was to try and use the body like a squirrel cage fan to pull air
through standard whistle mechanism located in the stem.
I thought it would be a good idea to actually make a regular whistle so
I’d know, if it didn’t work, where the problem was.
As there had just been an article in the AAW Journal on making whistles I
sort of followed that. It worked
fine. But I found the constant tone
too musical to demand attention.
I thought of a standard referee’s whistle with the ball
inside, and assumed from the shape (wrongly, as it turned out) that the ball
traveled in a circle to interrupt the tone every time it passed the slot.
So I tried using a 1/2” ball end mill instead of a drill to bore the
hole, and also used the ball end mill on the end of the fillip (the flattened
dowel that fits into the hole). I
turned a 5/16” ball and dropped it in the hole formed by the ball end mill
before inserting the fillip. I was
pleasantly surprised that it worked just fine (well, after a little tweaking).
The only real need I had for a whistle was when kayaking.
I figured a soaked wooden whistle would fail to work (and if I flipped
over into the water that’s when I’d really need it) so I tried making one out of
an acrylic pen blank. With acrylic
in particular, when the fillip was flattened it tend to be a little too loose to
stay in place when testing how far to insert it into the hole.
As I’d just been testing whistling top bodies with a straw I thought to
use a piece of tubing to blow the whistle, which allowed me to keep fingers on
the fillip to keep in in place. The
tubing was from a coil of vacuum line and the curve of the tubing put the
whistle notch in my line of vision.
That’s when I discovered that the ball didn’t go in a circle.
It just went up and down rapidly below the notch opening.
Presumably the air streaming rapidly over the hole creates a drop in air
pressure from the venturi effect (or maybe it’s like an airfoil?) which sucks
the ball into the opening, which then occludes the airflow, which allows the
ball to drop to repeat the process.
So I didn’t really need the ball end mill.
I had trouble getting a decent surface on the bandsawn
notch of the acrylic (at least not quickly enough to suit myself).
It occurred to me that turning eccentrically would let me sand and polish
the notch on the lathe. Once I’d
come up with an adjustable eccentric mount (or rather entirely too many of them)
I decided I might as well turn the air channel on the fillip that way as well.
And turning eccentrically also let me sculpt the body of the whistle
instead of just turning a bail for a lanyard on the end.
The wild patterns of the acrylic rather clashed with an eccentrically
turned body so I returned to using wood for this article.
Main Photo:
Completed Holly and Acrylic Warbling Whistles.
Briefly
First make an eccentric mounting jig.
See References for several to choose from.
Two blanks are cut from 3/4” square stock.
A 2” blank is turned into a ball, then a fillip blank, then modified
eccentrically to make an air passage.
A 3” blank is drilled to make a sound chamber.
The drilled hole is plugged so that the blank can be turned eccentrically
to cut the notch. Then the hole is
loaded with the ball and fillip and tested to find the right fillip position,
which is then glued in place. The
mouthpiece is turned eccentrically.
The blank is then reversed to turn the lanyard end in several steps.
Lastly modifications to the procedure to make an acrylic whistle and
other variations are discussed.
Turning the Ball
Cut a 2” long blank for the ball and fillip, and a 3” long
blank for the whistle body from 3/4” square turning stock as in Figure #1.
A strong fine grained diffuse porous hardwood would work best.
To get an opening in the notch arced enough that the ball can occlude the
airflow a wood that can be cut to an acute angle is required.
In the pictures I’m using Holly.
You could use a blank longer than 2” for the ball and fillip and have
more for the chuck to hold, but I designed the procedure to also work for
acrylic pen blanks.
Figure #1: The
blanks cut to length.
Visit Whistle Jigs (see References) and pick out and make a
system for mounting the whistle blanks eccentrically.
In the photos I’m using the Eccentric Sliding Chuck.
Draw diagonal lines to find the center of the ball and
fillip blank and make a dimple at the center with an awl.
With the aid of a cone tailstock center mount the blank centered in the
chuck so that about 1” of the blank protrudes as in Figure #2.
You can slide the chuck so that the dimple lines up with the tailstock
cone center tip. Turn most of the
protruding part of the blank round with a spindle roughing gouge. You could just
cut the ball by eye alone but I’m using a modified version of Myron Curtis’
method where the blank is first reduced to a rotated octagon the ball fits in.
Figure #2:
Mount the blank centered for turning the ball.
Using a parting tool and your preferred spindle turning
tool, reduce the blank to 5/16” diameter.
Cut slightly deeper a parting tool width at the tailstock end.
Then measure 5/16” away from the shoulder of this cut and mark with a
pencil as in Figure #3.
Figure #3:
Turn the blank to the ball diameter and mark the length of the ball.
Now set your calipers to 0.12” (which is 0.38 of the ball
diameter) and make parting tool cuts beside both ends of the ball to that
diameter. Also mark this width with
a pencil in the middle of the cylinder as in the left image of Figure #4.
Use a spindle gouge to make straight cuts between the pencil marks
and the shoulders of the parting tool cuts.
You can then make pencil marks in the middle of each surface as in the
right image of Figure #4 so you know where not to cut when rounding over the
ball. Then round over the ball.
Cut off the tailstock end stub and round over that end.
Sand the ball smooth as in Figure #5. Last cut off the ball and sand the
cut off end by hand. The ball is
quite small and hard to find. You
may wish to do the final cut-off by hand if you can’t hang on to it with fingers
of one hand whilst cutting if off with a tool in the other.
You also might wish to tape the ball to your workbench so it doesn’t get
lost while you’re working on the other parts.
Figure #4:
Turn the ball blank to a cylinder, then to a rotated octagon.
Figure #5:
Round over the corners of the rotated octagon to make a ball.
Turning the Fillip
Remount the blank so that a bit more than 7/8” protrudes
from the centered chuck as in Figure #6.
Turn the protruding portion to 1/2” diameter as in Figure #7.
Figure #6:
Remount the blank to turn the fillip.
Figure #7:
Turn the fillip to 1/2” diameter.
Back off the tailstock center, and slide the chuck so that
it is 1/8” eccentric. Bring up the
tailstock center again for support as in Figure #8.
Use a skew or spindle gouge to form the air channel as in Figure #9.
It’s difficult to specify how much to remove and also difficult to
measure when turning eccentrically.
So stop the lathe frequently and check visually until it looks like the photo.
If you want to measure you could drill a 1/2” hole in thin scrap wood and
cut it in half so the hole is a semi-circle.
Hold the scrap against the fillip.
The gap should look like a smile (or frown, depending on orientation) and
should be about 3/64” (or 0.04” or a little less than 1/16”)
Figure #8:
Mount the fillip blank 1/8” off center.
Figure #9:
Turn the air channel.
Return the chuck to center.
Use a 1/2” ball end mill as in Figure #10 to hollow the end of the
fillip. This makes the back of the
notch more like a circle, and gives the ball room to get in to occlude the
airflow. If you don’t have a ball
end mill you could use a small bowl gouge, or a wedge or cove tool.
Figure #10:
Hollow the end of the fillip.
Remount the fillip blank in the chuck a parting tool width
past the fillip as in Figure #11.
Use a standard parting tool and reduce the diameter to about 3/8” (less than the
air channel). Then use a 1/16”
parting tool to part off the fillip.
The nub left will allow you to grip the fillip for adjustment with a pair
of needle nose pliers. Figure #12
shows the turned ball and fillip.
Figure #11:
Remount the fillip blank for parting off.
Figure #12:
The completed ball and fillip.
Turning the Air Chamber
Find the centers of both ends of the Whistle blank by
drawing diagonal lines. Make a
small dimple at the center of each end.
Mount the whistle blank in the centered chuck with the aid of the dimple
and tailstock center with about 1-3/4” protruding from the face of the chuck.
Then turn the exposed portion of the whistle blank round as in Figure
#13. Sand and optionally polish the
turned portion of the blank.
Figure #13:
Mount the whistle blank and turn the exposed portion round.
Mount a combined drill and countersink (or other centering
drill) in the tailstock and drill a starter hole for drilling the sound chamber
as in Figure #14. Place tape (or
another depth indicator) 1-3/4” from the tip of a 1/2” drill.
Then mount the drill bit in a tailstock mounted drill chuck and drill to
1-3/4” depth as in Figure #15.
Figure #14:
Use a centering drill to start the sound chamber hole.
Figure #15:
Drill 1-3/4” deep with a 1/2” drill bit.
Make a plug for the sound chamber as seen in the inset of
Figure #16 which will allow you to use tailstock support when turning the notch,
and will back up the wood fibers of the edge of the notch resulting in a cleaner
edge. You can reuse the plug
several times. Take off the 4-jawed
chuck holding the whistle chuck and whistle blank and turn the plug between
centers. Mount a blank that’s
nominally 1” x 1” x 2-1/2” between centers and turn round.
Then turn 1-5/8” of the blank from the tailstock end to 1/2” diameter.
Adjust for a snug fit with blue tape if required.
Ensure that the shoulder of the plug contacts the end of the whistle
blank. A wood that contrasts with
your whistle blank will make it easier to see how big your opening into the
sound chamber has become.
Make a pencil mark 3/4” from the end of the blank (only on
the side where the notch will be cut, or put blue tape around the whistle blank
and mark the tape). Now slide the
chuck to 1/4” off center and insert the plug.
Then bring up the tailstock center for support as in Figure #16.
Figure #16:
Mount the whistle blank for notch turning with the aid of the plug shown in the
inset.
Use a skew or spindle gouge to cut the notch.
The cut at the pencil mark 3/4” from the end should be vertical.
The slope needs to be acute so that the opening is a high arch (almost a
semi-circle). Using black paper for
a background and a spotlight on the notch as in the top image of Figure #17 will
help you see how the cut is progressing.
The spotlight I’m using is a cheap LED USB light plugged into an excess
USB power block. The power block is
plugged into an extension cord with a 1” rare earth magnet on the other side.
You should still stop the lathe frequently to check how big the opening
has become and its shape. The
completed notch is shown in the bottom image of Figure #17.
Sand and optionally polish the notch.
Figure #17:
Turn the notch with the aid of a black background and spotlight.
Fitting the Fillip and Turning the Mouthpiece
The position of the fillip in the sound chamber is critical
to both getting a loud whistle and having the tone warble.
The only way to find the correct position is to test it.
That means the fillip has to fit tightly enough in the sound chamber to
stay put when you blow in it.
Cutting away some of the fillip blank for the air passageway tends to make the
fit a little loose for this. You
can tighten it back up with a small piece of blue tape (but not over the air
passageway) as shown in Figure #18.
Figure #18:
Shim the fillip with blue tape if needed for a tight fit while testing.
Drop the ball into the air chamber and insert the fillip.
There’s not much to grab of the fillip when it’s in, so a pair of needle
nose pliers would be handy. Make
sure that the air passageway is aligned with the sharp edge of the notch, and
that it’s far enough in that the ball can’t drop out.
Then try blowing the whistle.
If you start to get a tone which then stops (when blowing hard) try
pushing the fillip in a little bit more, but I’ve not discovered a substitute
for playing with the position. If
you get a tone but just can’t make it warble, you may have to return the notch
to a more acute angle. Once you’re
happy with the tone and warble, mark the position of the fillip with a pencil as
in Figure #19. Pull the fillip back
out and remove the tape. Put a thin
coat of glue on the fillip (but not on the air passageway) and reinsert to the
mark. Let the glue cure before
proceeding.
Figure #19:
Mark the satisfactory position of the fillip.
Mount the whistle blank in the sliding chuck so that it’s
1/4” off center with the high point directly opposite the notch.
The fillip stub is too small to allow tailstock support with a cone
center, but you can bring up a cone center for support as in Figure #20.
Figure #20:
Mount the whistle blank 1/4” eccentric in the chuck with a cone tailstock center
for support.
Turn a half-cove to form the mouthpiece as in Figure #21.
Be sure to leave about 1/8” between the vertical end of the notch and the
start of the cove at full diameter so you can mount the blank straight when
turning the lanyard end of the whistle.
Stop the lathe frequently to check how it looks.
Then cut off the protruding end of the fillip as in Figure #22.
Sand and optionally polish the cove and end.
Figure #21:
Turn a half cove to form the mouthpiece.
Figure #22:
Cut off the protruding fillip.
Turn the Lanyard End
Reverse the whistle blank and center the chuck with the aid
of the cone tailstock center and dimple at the cross diagonal lines at the end
as in Figure #23. Insure that a
full diameter of the blank is engaged by the chuck on both in front and behind
the notch. If the chucking system
you’re using does not allow this, then use a split PVC sleeve (see References)
to bridge the notch and then mount in the chuck.
Figure #23:
Reverse and center the whistle blank.
Turn the rest of the whistle blank round.
Disguise any slight errors in centering by turning a mini-cove or another
feature at the junction as in Figure #24.
Sand and optionally polish the newly turned portion of the blank.
Figure #24:
Turn the lanyard end round with a mini-cove to disguise the transition.
Slide the chucks so that it is 1/4” eccentric.
Rotate the whistle blank so that the eccentricity is directed the same
way as when you turned mouthpiece.
The cone tailstock center point should engage the blank on the diagonal line
drawn on the blank earlier as in Figure #25.
Figure #25:
Mount the blank eccentrically to sculpt the lanyard end.
Use a spindle gouge to turn a half-cove blending into a
straight cut in the lanyard end as in Figure #26.
As the blank was 3” long and drilled 1-3/4” deep, start the cove no more
than 1-1/8” from the end. Sand and
optionally polish the newly turned surface.
Figure #26:
Turn a half-cove on the lanyard end.
Withdraw the tailstock so you can draw a line on the end of
the blank between the points of the pointed oval shape.
Change the eccentricity of the chuck so that the tailstock center engages
the blank at the intersection of the line you just drew and the diagonal line
drawn earlier as in Figure #27.
This way the lanyard ball will be centered on the sculpted end of the blank.
Figure #27:
Remount the blank to turn a ball for the lanyard.
Define the extents of the ball with V-cuts and flatten the
points of the pointed oval shape where the ball will be.
This way you won’t have to try and start the drill on a point and will be
able to turn away any drill breakout.
Drill a 1/8” hole through the future ball as in Figure #28.
The hole should go across where the points were.
It should also be centered between the V-cuts defining the ends of the
ball.
Figure #28:
Drill a lanyard hole at the end of the blank.
Finish turning the lanyard ball as in Figure #29, then sand
and optionally polish the ball.
Then remove the whistle from the chuck.
If you’ve been using friction polish as you turn you probably will have
to touch up a few areas and then buff them.
The completed whistle is shown in Figure #30.
Figure #29:
Turn the ball.
Figure #30:
The completed whistle.
Variations
An acrylic pen blank can be used to make a waterproof acrylic whistle.
-
Unless you pick a solid color, the patterns of the acrylic tend to conflict with complicated shapes, so I suggest using a plain round end and ball at the lanyard end.
-
When drilling for the sound chamber, use a slow speed and pre-drill with a 15/32” drill bit or heat from drilling may result in a bumpy hole that is too large.
-
I found that a negative rake scraper gave a good surface that didn’t require a lot of sanding because of a pecked-out surface. You don’t need to buy one—a skew on its side or the nose of an upside down gouge will work. Keep the speed (thus the heat) down when sanding.
-
You may wish to turn the entire whistle blank round first as in the next section.
An alternative turning
sequence is to turn, sand, and polish the entire whistle blank
first, especially if you find a mini-cove transition element distracting.
Be sure to make diagonal lines on the ends of the blank before turning it
round as they’ll help you keep the various eccentric mountings aligned.
If you don’t enjoy making
jigs (no accounting for taste…) and don’t plan to make more than a
whistle or two you could turn between centers.
Make the blanks at least an inch longer to allow for nubs, and use cup
centers for drive and tailstock center.
References
Whistle Jigs:
http://www.DavidReedSmith.com/Articles/Whistle/WhistleJigs/WhistleJigs.html