PSN-L Email List Message

Subject: Homebrew AS-1 seismometer
From: "Dewayne Hill" n0ssy@...........
Date: Sun, 27 Mar 2005 19:49:52 -0700


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.

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