Shay Plumbing X -Whistle
Nelson Riedel Nelson@NelsonsLocomotive.com
Initial: 12/29/03 Last
There's snow on the ground and it's too cold to do any more steaming
tests so decided to do some of the unfinished plumbing (before the spouse
finds something to keep me busy). The whistle valve will
finish off the shelf above the rear cylinder and the whistle will help with
laying out the right running board.
Some months ago I learned that the air tank on the right side of
Kenneth's locomotive was really a whistle. I then read The Whistle chapter in SO YOU
WANT TO BUILD A LIVE STEAM LOCOMOTIVE (referred to as the text
in the following description) and learned that whistle
can't be scaled without raising the pitch. A design using a
1.5" piece of thin-wall plumbing pipe about 10 inches long is
presented and seems to match the design used by Kenneth. Castings
for this whistle are available from Coles. This design
divides the tube into four sections of different lengths to make a four
tone or four chime whistle. The overall whistle length determines the
lowest frequency tone. The tube diameter is related to
the whistle volume.
Next, some photos of the the Cass Shays were examined to try to
determine the size of the air tank. The next photo shows the tank on
Cass 5, which scales to about 10 inches long and a little
over 2 inches diameter.
The next step was to check out the various tone combinations listed in
the text and to select one for the Shay whistle. I tried some of the variations of the 4-chime
cords on the organ. Have to
admit that none sounded very good and none sounded like a whistle. (
I'm tone deaf so not surprised with this result.) The whistle
chapter was written by J F Nelson and he mentioned experimenting with
variations so decided that the whistle listed as the one he used would be
a reliable choice. The tones and tube lengths for J F Nelson's
|F# (349 Hz)
|A (440 Hz)
|C (523 Hz)
|D# (622 Hz)
The text mentions that these lengths are correct for steam.
(Suspect that if you try formulas from your old college physics text that
are for air you'll get different lengths.)
So, the whistle will be about 10" long including the throat
assembly ----- a close match to the air tank on Cass 5. The
next task was to determine the diameter. I wanted
to make it about 2" diameter but suffered sticker shock when checking
out the price of 2" OD brass tubes. And then there's the
brass rod needed to make the throat assembly. Some brass
strips are also needed for the vanes inside of the tube; the strip width
the same as the tube OD. I was designing a steam powered water
pump at the same time as I was working on the whistle and had decided to
use some 2" OD brass rod (~$40 a foot) and 2" X 1/8" brass strips for the
pump. I found
a 2" OD - 1 7/8" ID stainless steel tube from McMaster-Carr for
about $12 so decided to go with a 2" OD whistle.
Those of you with Nelson's text can refer to the drawings in The
Whistle chapter. I don't want to reproduce those drawings here as
it'd likely violate the copyright. Besides, that text is a
wealth of information for us novices so advise you all to go buy
one. In place of the drawing I'll show the sub assemblies first and
then show how some of the pieces were fabricated.
The vanes and the ends are made from the 2" X 1/8"
strip. The tube is 2" OD Stainless steel. The
vane assembly is pressed into the tube and the throat (on the
left) is screwed onto the end of the vane assembly. The throat
is turned from 2" OD brass rod. The hole in the throat is
threaded 3/8"-24 matching the 1" long stud on the end of the
vane assembly. The throat is 7/8" long with a 1.67" diameter recess
bored 7/16" deep. The nipple is 1/4" MTP. The left
1/2" of the vane assembly is turned to 1.66" (0.10" less than
the recess in the throat ) with the end plate turned at a 45 degree angle.
|Cutting the Vanes and Ends: The brass strip was cut on the band
saw and then squared off using the end mill as shown on the
right. The vanes were cut 1/8" longer than the longest
length in the table above to allow for 1/16" deep slots in the end
|This shows milling the 1/8" wide 1/16" deep slots in one of
|This shows cutting a 1/8" wide slot half the length of one
of the vanes. Each vane has one of these cuts.
|Slots were milled 1/16" deep in the vane to accommodate the stops for
the higher tones. The length show in the table above was adjusted
1/16" to allow for the slot in the throat end.
|The 3/8 stud was silver soldered in the throat end.
|This shows the parts of the vane. The little squares on the
upper right are the stops for the higher tones.
The next step was to press the vane assembly into the tube. I used
a 0.001" interference ----not much. The plan was to use a little Loctite
if it was loose. I heated the tube to 400 degrees in the oven,
held it with a thick towel and slid the vane into position. After the
tube cooled (or vanes warmed) the vane was held firmly. The throat was then screwed on.
The next photo shows the assembled unit.
|Finishing the End: The ends of the tube purchased from
McMaster-Carr were cut square. I couldn't saw the end
square and it couldn't be mounted easily in the lathe so I cut the
tube extra long, inserted the vane and then mounted the assembly
back in the lathe (using the same setup as used to turn the vanes)
and turned the end of the tube flush with the head. If I
would have checked the photo on the right I'd have left the tube
stick out about a quarter inch to give a recessed end. Maybe
|Mount: The mounting blocks were cut from aluminum.
The photo on right shows a fly cutter being used to mill a 1"
radius recess in a 1" thick aluminum block. The
block was later sawed in half and the halves milled to a width of
|This photo shows a strap and a finished block. The strap is 0.25" wide 0.046" stainless
steel. I don't have a shear so I sawed the piece extra wide on
the band saw and then finished the edge on the mill. The screws
are 4-40 stainless steel. The heads were cut off the screws,
ends pounded flat with a hammer and secured to the straps using 1/16" brass
rivets. The screws and rivet ends were then silver
soldered to the straps. The recesses in the
ends of mounting block are for the screws at the ends of the
straps. This scheme gives a very nice overall
|Valve: The setup shown on the right was used to test
the valve and whistle. The valve follows Kenneth's design except for
the operating lever. The black part of the lever was
turned from a Delrin scrap. The elbow next to the whistle
has a small hole (#56 drill) as per the text. The hole is to
drain any condensate; apparently one doesn't want to wet this
The whistle sounded really good on air after the throat was adjusted (it
drove the workshop cat into hiding and brought the spouse from the other end
of the house). A concern at this point is that the text
indicated the whistle sounds better on steam than air. Maybe I
screwed up and this one will sound better on air.
It'll have to wait --- too cold to drag the shay outside to make
|Installation: The walkways had been temporarily installed and
the order of unions and elbows arrived from LSM so it was time to do
the installation. The whistle was mounted to the walkway
first. It's positioned a little forward that the air tank on
Cass No 5; I though it looked a little better in this
position. The steam pipe runs along the walkway to near about
the middle of the rear cylinder then goes up and through the shelf
to the whistle valve. There is a union in the line next to the
elbow with the drain hole.
|This shows the valve mounted on the shelf. The pipe
out the side of the valve goes through a union and elbow and then
down to the walkway to another elbow and then on out to the
whistle. The input comes off a shutoff valve on the
turret through an elbow and union and then a couple more elbows into
the top of the valve.
The valve was modified to incorporate a small spring to hold the
valve off under low pressure. This was necessary because
the lever sticks out horizontally further than on Kenneth's design
causing a greater upward force on the ball. The plug in the top was
shortened about 1/8" to make room for the
|This whistle valve location worked out well. It's in a
central location but doesn't interfere with any of the other
Much of the time the boiler in pressurized with compressed
air. It's nearly impossible for a male to walk by without
giving the whistle a little toot.