I just completed a homebrew AS-1 seismometer.

I must say the most challenging part was trying to find a boom support =
spring.

Having no engineering degree so I was left to do the trail and error =
method. I got very lucky. I just had a new LOWES lumber/hardware store =
open very close to me.

Being a new store their stock was full and complete. I found a spring =
manufactured by Century Spring Corp.
The part number on the package is "C-219". I purchased two of these =
springs.=20

I had to do some resizing of these springs. The spring is 4.5" long. I =
cut about 3/8" off of each coil. I then spread the coils of each spring =
just far enough apart to mesh them
together (about a 1/2" overlap.)  I happened to have a 1/2" i.d. x 1" =
spacer in my junk bin so I slid the spacer over the meshed coils so they =
will not separate.

I ordered a coil and magnet for Larry. The amplifier is from the =
following URL http://users.viawest.net/~aloomis/seismom.htm a power =
supply for this amplifier=20
can be found at http://users.viawest.net/~aloomis/seisprea.htm .

When I started this project I requested a catalog from Century Spring. I =
can not find a spring with a C-219 part number, but there is a spring =
with the part
number of 302 that is a very close match. Another spring that could be =
tried is the 119. This one would have to be cut to the desired length. =
Century Spring has
a minimum order of $30.

I must say that the sensitivity appears to be superb as compared to my =
Lehman (but it's never been quite right after I rebuilt it.)

All of the mechanical bits were purchased from LOWES.

If you would like more information please contact me at =
n0ssy@........... and not through the PSN list server.



Dewayne Hill=20







I just completed a homebrew AS-1=20
seismometer.
 
I must say the most challenging part =
was trying to=20
find a boom support spring.
 
Having no engineering degree so I was =
left to do=20
the trail and error method. I got very lucky. I just had a new LOWES=20
lumber/hardware store open very close to me.
 
Being a new store their stock was full =
and=20
complete. I found a spring manufactured by Century Spring =
Corp.
The part number on the package is "C-219". I purchased two of these =

springs. 
 
I had to do some resizing of these =
springs. The=20
spring is 4.5" long. I cut about 3/8" off of each coil. I then spread =
the coils=20
of each spring just far enough apart to mesh them
together (about a 1/2" overlap.)  I happened to have a 1/2" =
i.d. x 1"=20
spacer in my junk bin so I slid the spacer over the meshed coils so they =
will=20
not separate.
 
I ordered a coil and magnet for Larry. =
The=20
amplifier is from the following URL http://users.viawe=
st.net/~aloomis/seismom.htm=20
a power supply for this amplifier 
can be found at http://users.viaw=
est.net/~aloomis/seisprea.htm=20
..
 
When I started this project I requested =
a catalog=20
from Century Spring. I can not find a spring with a C-219 part number, =
but there=20
is a spring with the part
number of 302 that is a very close match. Another spring that could =
be=20
tried is the 119. This one would have to be cut to the desired length. =
Century=20
Spring has
a minimum order of $30.
 
I must say that the sensitivity appears =
to be=20
superb as compared to my Lehman (but it's never been quite right after I =
rebuilt=20
it.)
 
All of the mechanical bits were =
purchased from=20
LOWES.
 
If you would like more information =
please contact=20
me at n0ssy@........... =
and not=20
through the PSN list server.
 
 
 
Dewayne Hill 
Westminster,=20
Co.