Date: Wed, 15 Dec 2004 09:42:21 -0800

Author: "Ann Hanks"

Subject: RE: Mechanical Resonance with Metal Blades


When I was teaching I made one using a squirrel cage fan on a 12VDC motor. I
screwed a bolt and nut between the fan blades to throw it off balance. Then
I mounted it to a board with hacksaw blades attached. I put a piece of foam
under the board on the hacksaw blade end and attached a hinge to the other
end of the board so I could clamp the hinge to a table, allowing the board
to move.

Ann Hanks
PASCO Product Development
-----Original Message-----
[] On Behalf Of John Mocko
Sent: Wednesday, December 15, 2004 6:13 AM
Subject: Mechanical Resonance with Metal Blades

Hello Tap-l,

I'd like to build a mechanical resonance demo using an old jigsaw (sabre
saw) motor to excite large metal blades of different lengths. The blades
would be something like hacksaw blades or larger that would vibrate and
reach resonance for different lengths as the motor speed is changed. I've
seen a similar design that someone on tap-l had where they used a drill
motor and an offset weight to vibrate the system. Does anyone have a
similar design for such a beast that can me a headstart on designing


John Mocko
Senior Teaching Laboratory Specialist (Lecture Demonstrations)
Department of Physics
University of Florida
Gainesville, Fl.
From Wed Dec 15 12:48:20 2004