Brett,  Thanks, that sound very logical, and something I had not =
considered.  Ted
  ----- Original Message -----=20
  From: Brett Nordgren=20
  To: psn-l@.................
  Sent: Wednesday, August 01, 2007 5:33 PM
  Subject: Re: Period and Hinges


  At 04:16 PM 8/1/2007 -0600, you wrote:

    Hi All,    Two new questions from me today.
    =20
    


    I did a simple test, using various hinges, foil, wire, razor blades =
and eyebolts.   I could and did see some difference in how long a =
pendulum would swing free.  I just moved the pendulum 6" and let it go =
counted the cycles until it stopped.
    Not very accurate, but I could see only about 20 percent different, =
between what I would call good and better hinges.
    I am not suggesting this test tell the whole story.   So if there is =
a study I would like to see it or hear about your own testing.   I was =
surprised there was not a greater different on my test.

  Ted,

  One possibility that I have heard about in connection with =
high-performance pendulum clocks, is that the mounting points need to be =
absolutely solid.  There can be a considerable loss of energy through =
'mushy' supports, which might make good hinges appear to perform nearly =
as badly as poor ones.

  I would guess that a concrete wall would make a pretty solid mount, =
though a wood one apparently does not.  Or perhaps a rigid steel frame =
sitting on a concrete floor might be good.

  Perhaps a year ago someone on the List was doing something similar and =
getting very long decay times, as I recall.

  Regards,
  Brett








Brett,  Thanks, that sound very =
logical, and=20
something I had not considered.  Ted

  
----- Original Message ----- 
  From:=20
  Brett=20
  Nordgren 
  
To: psn-l@.............. 
  
Sent: Wednesday, August 01, =
2007 5:33=20
  PM
  
Subject: Re: Period and =
Hinges
  

At 04:16 PM 8/1/2007 -0600, you wrote:

  
Hi=20
    All,    Two new questions from me=20
    today.
 
<clip>


  
I did a=20
    simple test, using various hinges, foil, wire, razor blades and=20
    eyebolts.   I could and did see some difference in how =
long a=20
    pendulum would swing free.  I just moved the pendulum 6" and =
let it go=20
    counted the cycles until it stopped.
Not=20
    very accurate, but I could see only about 20 percent different, =
between what=20
    I would call good and better hinges.
I am=20
    not suggesting this test tell the whole story.   So if =
there is a=20
    study I would like to see it or hear about your own =
testing.   I=20
    was surprised there was not a greater different on my=20
  test.

Ted,

One possibility that I have =
heard=20
  about in connection with high-performance pendulum clocks, is that the =

  mounting points need to be absolutely solid.  There can be a =
considerable=20
  loss of energy through 'mushy' supports, which might make good hinges =
appear=20
  to perform nearly as badly as poor ones.

I would guess that a =
concrete=20
  wall would make a pretty solid mount, though a wood one apparently =
does=20
  not.  Or perhaps a rigid steel frame sitting on a concrete floor =
might be=20
  good.

Perhaps a year ago someone on the List was doing =
something=20
  similar and getting very long decay times, as I=20
  recall.

Regards,
Brett