James
Years ago I tried to build one using an isometric drawing and STM's electronics. 
It worked well but not consistantly. I build the hinge using a music wire in a 
dumb bell fashion. I have to look at in storage to see how I made it. Here is a 
photo I took "back when". The sensor mass was not to large so the tension on the 
wire may not be as high as yours.  
http://www.seismicvault.com/sitebuilder/images/HINGE_12H.jpg
I'll find out what I did and get back to you.

 Regards
Barry
www.seismicvault.com






________________________________
From: JAMES C ALLEN 
To: psnlist@..............
Sent: Thu, April 5, 2012 9:08:03 AM
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER


Thanks Bob, Randy and Robert regarding ideas/ suggestions regarding making  the 
Spregnether hinge.  I will explore some of the options suggested to try  and 
have the brass drilled by one of the type of shops referenced that have the  
skill and equipment.
Again, thanks for your ideas
James Allen  
From: Robert Thomasson 
Sent: Thursday, April 05, 2012 4:43 AM
To: psnlist@.............. 
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER
  James,  not sure how you're trying to do the drilling, for holes that small 
you need a  small precision drill press with an accurate chuck.  It would 
probably take  more skill than I have to do it with a hand held drill.  My first 
thoughts  are to try and find a real jeweler or silversmith or gunsmith, they 
may have the  equipment to drill similar holes.  Or possibly an electronics 
assembly shop  that does printed circuit board work.  It wouldn't hurt to call 
machine  shops and ask, but most of them around here are more geared toward 
drilling 12"  diameter holes.

Dremel sells a small drill press accessory for their  variable speed Moto Tools 
that might work.  I think you'd need to use a  slow speed.  You'd still need to 
devise an accurate method of holding the  brass pieces while drilling and if it 
doesn't work and you don't have other uses  for the drill press you're out 
$100+.  


Bob



On Wed, Apr 4, 2012 at 9:45 PM, JAMES C ALLEN  wrote:

I know that this is a long shot, but does anyone have parts for an old    
Spregnether horizontal seismometer?  Specifically the lower wire    hinge.  The 
piece is a short wire with a round brass fitting at each    end.  I tried to 
make it myself using piano wire and round brass    stock.  But drilling the 
round brass stock to insert the wire into has    been fraught with failure thus 
far since the very small drill bits I purchased    at the hobby shop keep 
breaking,  Also, any advice on drilling an    approximately .030 diameter hole 
in round brass stock would also be    appreciated.  Do machine shops do this 
James
Years ago I tried to build one using an isometric drawing and STM's electronics. It worked well but not consistantly. I build the hinge using a music wire in a dumb bell fashion. I have to look at in storage to see how I made it. Here is a photo I took "back when". The sensor mass was not to large so the tension on the wire may not be as high as yours.  http://www.seismicvault.com/sitebuilder/images/HINGE_12H.jpg
I'll find out what I did and get back to you.
 
Regards
Barry
www.seismicvault.com



From: JAMES C ALLEN <jcallen1@...........>
To: psnlist@..............
Sent: Thu, April 5, 2012 9:08:03 AM
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER






Thanks Bob, Randy and Robert regarding ideas/ suggestions regarding making 
the Spregnether hinge.  I will explore some of the options suggested to try 
and have the brass drilled by one of the type of shops referenced that have the 
skill and equipment.
Again, thanks for your ideas
James Allen 


 

From: Robert Thomasson 
Sent: Thursday, April 05, 2012 4:43 AM
To: psnlist@.............. 
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER
 
James, 
not sure how you're trying to do the drilling, for holes that small you need a 
small precision drill press with an accurate chuck.  It would probably take 
more skill than I have to do it with a hand held drill.  My first thoughts 
are to try and find a real jeweler or silversmith or gunsmith, they may have the 
equipment to drill similar holes.  Or possibly an electronics assembly shop 
that does printed circuit board work.  It wouldn't hurt to call machine 
shops and ask, but most of them around here are more geared toward drilling 12" 
diameter holes.

Dremel sells a small drill press accessory for their 
variable speed Moto Tools that might work.  I think you'd need to use a 
slow speed.  You'd still need to devise an accurate method of holding the 
brass pieces while drilling and if it doesn't work and you don't have other uses 
for the drill press you're out $100+.  

Bob



On Wed, Apr 4, 2012 at 9:45 PM, JAMES C ALLEN <jcallen1@...........> 
wrote:


  

  

  

  
I know that this is a long shot, but does anyone have parts for an old 
  Spregnether horizontal seismometer?  Specifically the lower wire 
  hinge.  The piece is a short wire with a round brass fitting at each 
  end.  I tried to make it myself using piano wire and round brass 
  stock.  But drilling the round brass stock to insert the wire into has 
  been fraught with failure thus far since the very small drill bits I purchased 
  at the hobby shop keep breaking,  Also, any advice on drilling an 
  approximately .030 diameter hole in round brass stock would also be 
  appreciated.  Do machine shops do this kind of work?

  
James Allen