How to make a Megaphone – Cardboard Megaphone

Learn how to make a  Megaphone  –  Cardboard Megaphone – excerpt from the book “The Scientific American Boy” by A. Russell Bond

A sheet of light cardboard 30 inches square was procured.
At the center of one edge a pin was stuck into the cardboard, then a piece of stout thread was looped over the pin and the two ends were knotted together just 5 inches from the pin.
Another knot was also made 29 inches from the pin.

Now, with a pencil hooked into the loop, and resting first against the inner knot and then against the outer one, two arcs were drawn on the paper, one of 5-inch radius and the other of 29-inch radius.

How to make a Megaphone

A line was now drawn from the pin to the point where the longer arc met the right hand edge of the paper, and a dotted line was drawn from the pin to a point 1-1/2 inches from the edge at the other end of the arc.

From a point 1 inch to the left of the pin we then drew a line to the left end of the arc.
With a scissors we cut the cardboard along the arcs and straight lines, all but the dotted line, leaving a piece of the shape shown in Fig. 55.
Layout of Megaphone
This piece was rolled into a cone with the right edge 59 lapped over the left edge and lying against the dotted line.

In this position it was held by means of several brass fasteners of the kind shown in Fig. 56.
Brass FastenerA mouthpiece was formed out of a block of wood in which a large hole had been drilled.

The block was then cut away until the walls were quite thin. The hole was reamed out at the top, as shown in Fig. 57, and the outer surface was tapered so that the small end of the megaphone would fit snugly on it.

Megaphone Mouthpiece
The SCIENTIFIC AMERICAN BOY OR The Camp at Willow Clump Island
By A. RUSSELL BOND NEW YORK MUNN & CO., Publishers
1906

Read more

How to Build a Skiff – Wood Boat Plans How to Build a Skiff - Wood Boat Plans The following is a description of an easily constructed 12-ft. skiff, suitable for rowing and paddling. Thi...
Household Tips And Tricks – More than Three Hundre... Excerpt from the book:MOTHER'S'  REMEDIESOver One Thousand Tried and Tested Remedies from Mothers of the United States and Canada.By DR. T. J. RI...
What is Sap of Trees? The sap of trees goes upwardly, not because the tree is alive, but due to this property in the contact of liquids with a solid. It is exactly on the s...
What is air pressure? – Solids Liquids and G... Look out of your window.Is the air moving?It is probably moving enough to make the branches on the trees sway slightly.The weight of this air pressing...
Close Menu