In a message dated 11/23/02 8:06:15 AM GMT Standard Time, 
meredithlamb@............. writes:


> All these tilts, drift, instability all have a cause and effect.
> For myself; its usually the water/moisture in the ground and its
> variations of content which change the shape/tilt of the piers.
> All outside changes in temperature affects the ground moisture
> evaporation along with natural drainage, as does added rain/snow
> storms of course.  

Hi all,

Even with a perfect suspension most if not all of us would still have the 
limitations Meredith mentions above to deal with. For most of us probably the 
most effective way of getting a longer period Lehman to be stable would be to 
build a good pier. For those of us who have our Lehman sitting on the garage 
or basement floor this could probably best be done by chopping a big hole in 
the concrete floor so we could build a good pier. Perish the thought!! I 
would not dare even think about such a thing for my Lehman at my son's house 
in Florida where I am a guest: grandpapa who comes down from up north for the 
winter to escape shoveling snow and slipping on the ice and breaking bones 
fragile from old age. No way!!

But there is a way out, a way mentioned several times by Sean-Thomas 
Morrissey when he was still with us. He said amateurs might do well to 
forsake their favorite Lehmans for a vertical with a period of ~ 1 second. He 
was designing a leaf spring vertical about which he posted several long 
letters describing its advantages. A big advantage was an excellent leaf 
spring is readily available by removing the handle from a 14-inch plasterer's 
spackling trowel you can buy at Home Depot. Last winter I built a modified 
version of his leaf spring vertical by mounting one of the these excellent 4" 
X 14" flat springs on a base vertically and put enough lead on the other end 
to put a 90 degree bend in it so the other end was horizontal. I then mounted 
a coil, the winding for a 120 volt relay, on an outrigger so it dipped down 
between a the poles of a big Alnico magnet. I hooked this sensor coil to one 
of Dave Saum's A/D converter/amplifiers and used Allen Jones's Amaseis free 
software to record by computer in a Helicorder format just like you can see 
at: 

http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm 

By taking Sean Thomas's advice I eliminated all the problems with the garage 
floor instability and now it doesn't matter what kind of suspension I have on 
my abandoned  Lehman. I'll return to Orlando, FL next Saturday and set up the 
trouble free leaf spring vertical and record earthquakes. I'll let you know 
more about how it works then.

Best regards,
Cap
In a message dated 11/23/02 8:06:15 AM GMT Standard Time, meredithlamb@............. writes:





All these tilts, drift, instability all have a cause and effect.

For myself; its usually the water/moisture in the ground and its

variations of content which change the shape/tilt of the piers.

All outside changes in temperature affects the ground moisture

evaporation along with natural drainage, as does added rain/snow

storms of course.  




Hi all,



Even with a perfect suspension most if not all of us would still have the limitations Meredith mentions above to deal with. For most of us probably the most effective way of getting a longer period Lehman to be stable would be to build a good pier. For those of us who have our Lehman sitting on the garage or basement floor this could probably best be done by chopping a big hole in the concrete floor so we could build a good pier. Perish the thought!! I would not dare even think about such a thing for my Lehman at my son's house in Florida where I am a guest: grandpapa who comes down from up north for the winter to escape shoveling snow and slipping on the ice and breaking bones fragile from old age. No way!!



But there is a way out, a way mentioned several times by Sean-Thomas Morrissey when he was still with us. He said amateurs might do well to forsake their favorite Lehmans for a vertical with a period of ~ 1 second. He was designing a leaf spring vertical about which he posted several long letters describing its advantages. A big advantage was an excellent leaf spring is readily available by removing the handle from a 14-inch plasterer's spackling trowel you can buy at Home Depot. Last winter I built a modified version of his leaf spring vertical by mounting one of the these excellent 4" X 14" flat springs on a base vertically and put enough lead on the other end to put a 90 degree bend in it so the other end was horizontal. I then mounted a coil, the winding for a 120 volt relay, on an outrigger so it dipped down between a the poles of a big Alnico magnet. I hooked this sensor coil to one of Dave Saum's A/D converter/amplifiers and used Allen Jones's Amaseis free software to record by computer in a Helicorde
r format just like you can see at: 



http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm 



By taking Sean Thomas's advice I eliminated all the problems with the garage floor instability and now it doesn't matter what kind of suspension I have on my abandoned  Lehman. I'll return to Orlando, FL next Saturday and set up the trouble free leaf spring vertical and record earthquakes. I'll let you know more about how it works then.



Best regards,

Cap