Okay… Hopefully… These highlighted images will give you enough of an idea of
“How to Build an Adjustable Helmholtz Resonator Tube”. Here is the Legend and Component Information:
(1) The 10 MM X 1.50 MM Threaded Rod is what does the Moving… inwards and outwards through the Two Welded on Metric Nuts on either side of the Back Plate. Do NOT Weld The Rod to That Plate! You can quickly make adjustment under the Vehicle if you Weld a 10 MM Nut on the Very End of the Exterior of that Threaded Rod.
(2) The Front Plate in the attached images is 4” in Diameter to Scale and has a Hole Center Drilled to allow for a “J” Pipe Insertion… (Two “Yellow Plastic” Plates I'm using represent REAL Metal End Plates used in this Example). Both Plates eventually MUST be
Welded at their Outer Edges to the ends of a 4” X 40” Steel Pipe.
(3) All Imaged Fasteners (M10 X 1.50) showing
Sky BLUE DOTS MUST be Welded to the
THREADED ROD.
(4) All Imaged Fasteners (M10 X 1.50 showing
RED DOTS MUST be Welded to the
BACK PLATE.
(5) The In-Out Arrows define the Freedom of Movement allowed by the Threaded Rod.
(6) The
Black Plastic Plate is what MOVES inside of the Hollow 4” X 40” Length of Pipe. It gets Fixed and Welded to the Very End of the Adjustable 10 MM X 1.50MM Rod with opposite facing Flange Nuts for Stability.
(7) I did NOT have a 4” Pipe available to install all of this Example Gear into… so You’ll just have to use your Imagination.
(8) I would suggest using a thicker piece of 3/16” X 6” piece of Mild Steel Plate to cut out the Adjustable (Black Plastic) Plate as its thickness will be better for stability on the end of the Threaded Shaft and naturally… its OD will have to be ground down to be SLIGHTLY Smaller than the Inside Diameter of the 4” Steel Pipe. Make certain that the Adjustable Steel Plate travels easily into and out of the length inside of that 4" Steel Tube.
(9) Remember… It’s the Two “Yellow Plates” that get Welded to the Front and Back Ends of the 4” X 40” Hollow Steel Tube…
NOT That Black One!
(10) Do NOT Start Welding until all of these components are Pre-Fitted and Double Checked for their Positions and Follow the Orders of Assembly. Triple Check Yourself B4 Firing Up The Welder! Do NOT Use or Weld
Chrome Plated Fasteners as they will produce Toxic Halides and Chromate Gases that can KILL YOU if you accidentally breath in those Vapors!