Hi all,

BACKGROUND PIVOT:  Chris Chapman's newer horizontal designs with his lower
pivot being a boom end flat that is pivoting on a mast mounted
ball bearing seems to be a very ideal, reliable and much more stable
"standard pivot" for those of us endeavoring  to make a commonly used home
brew horizontal seismometer.  It was studied in 2008 by him, Charles Patton
and Brett Nordgren and briefly described by the web paper:
http://www.myeclectric.info/SeismoPivots/seismopivots.htm   and had many
other PSN description emails in that time period.

The question that comes up from all this is whether such a lower pivot/s
could be ~ reliably used in a home brew short period vertical
spring seismometer?  I note no reference to such a trial; but that doesn't
exclude that someones hasn't already experimented with such?
This excludes known boom mounted balls on a mast flat.  The size/weight of
the seismometer mass in mind is similar to that of the AS1.

I would also assume that it is likely necessary to have any such balls
mounted on the side of a mechanical support/s to fix the spring opposition.

It would necessitate two such pivots for maintaining vertical positional
reliability...i.e.; the "boom" would need to be "T" shaped to constrain
its otherwise undesirable lateral movement with only one pivot.

Meredith Lamb
Hi all,
=A0
BACKGROUND PIVOT:=A0 Chris Chapman's newer horizontal designs with=
 his lower pivot being a boom end flat that is=A0pivoting on a mast mounted=

ball bearing seems to be a very ideal, reliable and much more stable &=
quot;standard pivot" for those of us endeavoring=A0=A0to make a common=
ly used=A0home
brew horizontal seismometer.=A0 It was studied in 2008 by him, Charles=
 Patton and Brett Nordgren and=A0briefly described by the web paper:=A0 http://w=
ww.myeclectric.info/SeismoPivots/seismopivots.htm=A0=A0 and had many ot=
her PSN description emails in that time period.

=A0
The question that comes up from all this is whether such a lower pivot=
/s could be=A0~ reliably used=A0in a home brew short period vertical
spring seismometer?=A0 I note no reference to such a trial; but that d=
oesn't exclude that someones hasn't already experimented=A0with=A0s=
uch?
This excludes known boom mounted balls on a mast flat.=A0 The size/wei=
ght of the seismometer mass in mind is similar to that of the AS1.
=A0
I would also=A0assume that it=A0is likely=A0necessary to have any such=
 balls mounted on the side of a mechanical support/s to=A0fix the spring op=
position.
=A0
It would necessitate two such pivots for=A0maintaining vertical positi=
onal reliability...i.e.; the "boom"=A0would need to be "T&qu=
ot; shaped to constrain
its otherwise undesirable lateral movement with only one pivot.=A0
=A0
Meredith Lamb
=A0
=A0
=A0
=A0
=A0
=A0 
=A0
=A0
=A0
=A0