3b. Next, drill three y" holes
spaced equally ¹/3 of the way around
the 8½"-long, 2"-diameter pipe,
approximately 4" from the top of the
pipe. Space the holes evenly as you
did in Step 1c. Screw the ¼" bolts into
the holes and position them in and
out by turning them.
3c. To shape the bell’s edge, cut (with a lathe) or grind (with
a sander) a 30° angle into 1 edge of the 2"-diameter smooth PVC
coupling as shown here.
3d. To attain the desired tritone, you’ll need to cut the pipe so
the length of the 2"-diameter bell assembly, from the bottom of
the lip bevel to the inside top of the cap, is 8¼". Dry-assemble
the bell by connecting the top cap, the bell adjustment chamber
(the 2" pipe with adjusting screws), and the bell edge
(the 2"-diameter smooth coupling with 45° bottom edge).
Cut the pipe so that the overall length of the 2" bell assembly is
8¼" long. Disassemble after cutting the pipe to length.
3e. Now, to make the second smaller bell, repeat Steps 3a
through 3d, using the 1½" pipe, end cap, and smooth-to-smooth
coupling. For the tritone, cut the 1½"-diameter pipe such that
the total height of the bell is 5¾" from the lip bevel to the inside
top of the cap.
4. MAKE THE MANIFOLD AND ASSEMBLE THE WHISTLE
4a. Drill a ³/8" hole in the bottom of each tee fitting, as shown here.
Connect the manifold parts. The valve and openings at both ends
allow you to tune or “voice” each whistle individually without
disassembling the manifold.