Kay,

Excellent drawings on your pdf file!

Although I no longer operate anything, the music wire pivot approach is
indeed a excellent one.  One can
also use the same approach on a horizontal seismometer; as was done on the
old World Wide Seismograph
network horizontal Sprengnethers.  The old Sprengnether horizontal mass was
roughly 20 pounds; which
for horizontal home brew fans...eliminates weight friction problems with the
"usual" amateur pivot. Indeed, at
one time John Lahr also used such on a home brew horizontal years back when
he was in Golden, Colorado.
Although they take a while to build/use; they are zero maintenance and most
likely close to zero replacement if,
secured firmly.

With the use of a STRONG music wire holding pivot assembly, the mass weight
can be increased very substantially
to make it remain in space ~ (relatively) motionless, (inertia), while the
earth moves.  The trade off could of
course involve finding a better or more suitable spring than used in the AS1
or similar home brew replications.

Take care, Meredith Lamb



On Sun, Jan 23, 2011 at 3:01 PM, Kay Wyatt  wrote:

>  Hi Richard,
>
> Chris Chapman has provided considerable guidance to me and suggested two
> possible alternatives to the knife edge of the AS-1.
>
> In the first example, he suggested clamping a standard razer blade to BOTH
> the horizontal arm and the vertical support.  The razer blade flexes very
> nicely with little friction.  Since I build seismometers for schools which
> sometimes have eager hands around them, I chose not to use a razer blade.
> Even though the ends can be dulled, if the arm is bent too far it can snap
> and I was afraid of pieces flying off into eyes.
>
> The second design that Chris suggested I thought was so clever it was close
> to magic.  It is hard to describe, so I just uploaded a PDF file that has
> the design drawings that I made for my seismometer.  The pivot mechanism is
> shown on page two of the PDF file.  You can see from my work that it had
> strong influence from Chris Chapman who I consider to be my good friend.
> Here is the link to the PDF file:
>
> http://www.oregonshakes.com/temp/DesignDrawings4.pdf
>
> Enjoy!
> Kay Wyatt
>
>
>
>
>
Kay,

Excellent drawings on your pdf file!

=
Although I no longer operate anything, the music wire pivot appr=
oach is indeed a excellent one. =A0One can
also use the same appr=
oach on a horizontal seismometer; as was done on the old World Wide Seismog=
raph
network horizontal Sprengnethers. =A0The old Sprengnether horizontal m=
ass was roughly 20 pounds; which
for horizontal home brew fans...=
eliminates weight friction problems with the "usual" amateur pivo=
t. Indeed,=A0at
one time John=A0Lahr also used such on a home brew horizontal=A0years =
back when he was in Golden, Colorado.
Although=A0they take a whil=
e to build/use; they are zero=A0maintenance and most likely close to zero r=
eplacement if,
secured firmly. =A0

With the use of a STRONG =
music wire holding pivot assembly, the mass weight can be increased very su=
bstantially
to make it remain in space ~ (relatively) motionless,=
 (inertia), while the earth moves. =A0The trade off could of=A0
course involve=A0finding=A0a better or more suitable spring than used =
in the AS1 or similar home brew replications.

Take=
 care, Meredith Lamb=A0




On Sun, Jan 23, 2011 at 3:01 PM, Kay Wyatt <kwyatt@.............> wrote:








Hi Richard,
=A0
Chris Chapman has provided considerable guidance =
to me and=20
suggested two possible alternatives to the knife edge of the AS-1.=A0=20

=A0
In the first example, he suggested clamping a sta=
ndard=20
razer blade to BOTH the horizontal arm and the vertical support.=A0 The raz=
er=20
blade flexes very nicely with little friction.=A0 Since I build seismometer=
s=20
for schools which sometimes have eager hands around them, I chose not to us=
e a=20
razer blade.=A0 Even though the ends can be dulled, if the arm is bent too=
=20
far it can snap and I was afraid of pieces flying off into eyes.
=A0
The second design that Chris suggested I thought =
was so=20
clever it was close to magic.=A0 It is hard to describe, so I just=20
uploaded=A0a PDF file that has the design drawings that I made for my=20
seismometer.=A0 The pivot mechanism is shown on page two of the PDF=20
file.=A0 You can see from my work that it had strong influence from Chris=
=20
Chapman who I consider to be my good friend.=A0 Here is the link to the PDF=
=20
file:
=A0
http://www.oregonshakes.com/temp/DesignDr=
awings4.pdf
=A0
Enjoy!
Kay Wyatt

=A0
=A0

  

<=
/blockquote>