PSN-L Email List Message

Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER
From: "JAMES C ALLEN" jcallen1@...........
Date: Thu, 05 Apr 2012 20:33:11 -0700


Thanks Chris.  Your clear and detailed recommendations  sure make sense =
to me.  However, with my age and infirmities and the lack of a drill =
press I have been fortunate in Jim Hannon, who has the equipment, to =
offer to do it for me.  I really appreciate your thoughtful =
recommendations and all the list members who have been so responsive and =
kind with their suggestions.  It truly is great to be a part of a hobby =
and list with such wonderful people such as you.
Thank you so much.
James Allen=20

From: chrisatupw@..........
Sent: Thursday, April 05, 2012 6:16 PM
To: psnlist@.................
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER

From: JAMES C ALLEN jcallen1@...........
Sent: Thu, 5 Apr 2012 5:56
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER


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.=20
James Allen

Hi James,=20
    The smallest drills that I can buy off the shelf are 13.5 thou. I =
suggest that you use steel bits. The tungsten carbide ones are VERY =
brittle - and expensive. You need a miniature high speed drill, a drill =
press and a small vice to clamp the workpiece. I use a 1/8" chuck 12 V =
Reliant drill running at about 8,000 RPM, bought for drilling PCBs. =
Centre punch the end of the brass rod and lower the running drill SLOWLY =
and drill the metal SLOWLY, with frequent withdrawls to clear the swarf. =
You do NOT use any oil or lubricant. It should NOT be a really difficult =
job, but you probably can't use a hand held Dremel drill. Assuming that =
you are soldering the wire in place, clean it with fine emery paper and =
tin the ends with a fairly active solder paste. Then wash / scrub the =
flux off and assemble the joint with rosin cored circuit board solder =
and a different soldering iron - you don't want any corrosive residues. =
Sorry that I can't be of more practical help - I am on the wrong side of =
the Atlantic ! Do you know any local HAM radio operators who might have =
a circuit board press drill ?
    Do check the exact dimensions of the origional flex link as =
accurately as possible. I use sliding callipers accurate to 0.5 thou. =
What was the actual wire diameter used ? The nearest piano wire size =
seems to be 0.025".=20
    Regards,=20


Thanks Chris.  Your clear and detailed recommendations  = sure make=20 sense to me.  However, with my age and infirmities and the lack of = a drill=20 press I have been fortunate in Jim Hannon, who has the equipment, to = offer to do=20 it for me.  I really appreciate your thoughtful recommendations and = all the=20 list members who have been so responsive and kind with their = suggestions. =20 It truly is great to be a part of a hobby and list with such wonderful = people=20 such as you.
Thank you so much.
James Allen
 
Sent: Thursday, April 05, 2012 6:16 PM
Subject: Re: SPREGNETHER HORIZONAL = SEISMOMETER
 
From:=20 JAMES C ALLEN jcallen1@...........
Sent: = Thu, 5 Apr=20 2012 5:56
Subject: Re: SPREGNETHER HORIZONAL SEISMOMETER

Does anyone have = parts for=20 an old Spregnether horizontal seismometer?  Specifically the lower = wire=20 hinge.  The piece is a short wire with a round brass fitting at = each=20 end.  I tried to make it myself using piano wire and round brass=20 stock.  But drilling the round brass stock to insert the wire into = has been=20 fraught with failure thus far since the very small drill bits I = purchased at the=20 hobby shop keep breaking,  Also, any advice on drilling an = approximately=20 ..030 diameter hole in round brass stock would also be appreciated. =
James Allen
 
Hi James,
 
    The smallest drills that I can buy off = the shelf=20 are 13.5 thou. I suggest that you use steel bits. The tungsten carbide = ones are=20 VERY brittle - and expensive. You need a miniature high speed drill, a = drill=20 press and a small vice to clamp the workpiece. I use a = 1/8" chuck=20 12 V Reliant drill running at about 8,000 RPM, bought for drilling PCBs. = Centre=20 punch the end of the brass rod and lower the running drill SLOWLY and = drill the=20 metal SLOWLY, with frequent withdrawls to clear the swarf. You do NOT = use any=20 oil or lubricant. It should NOT be a really difficult job, but you = probably=20 can't use a hand held Dremel drill. Assuming that you are soldering the = wire in=20 place, clean it with fine emery paper and tin the ends with a fairly = active=20 solder paste. Then wash / scrub the flux off and assemble the joint with = rosin=20 cored circuit board solder and a different soldering iron - you don't = want any=20 corrosive residues. Sorry that I can't be of more practical help - I am = on the=20 wrong side of the Atlantic ! Do you know any local HAM radio operators = who might=20 have a circuit board press drill ?
    Do check the exact dimensions of the = origional=20 flex link as accurately as possible. I use sliding callipers accurate to = 0.5=20 thou. What was the actual wire diameter used ? The nearest piano wire = size seems=20 to be 0.025".
 
    Regards,
 
    Chris=20 Chapman

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