All, 

Please see answers to Chris' questions below.

Thank you.

 -------------- Original message ----------------------
From: ChrisAtUpw@.......
> In a message dated 04/08/06, jr_brady@........... writes:
> 
> > I'm offering the following parts for sale to the group.  They were used in
> > the construction of a Lehman sensor. 
> > Thank you,
> > Jason Brady   Lynnwood, WA USA
> > jr_brady (at) comcast (dot) net
> 
> Hi Jason,
> 
>        If you would specify the sizes / quantities outlined below as queries, 
> it would be a great help, please. Otherwise we don't know what you are trying 
> to sell! 

Sorry, I thought it was clear that "(n)" specifies quantity of an item.  I don't understand what you mean by "queries."

> 
>        There are maybe a dozen sizes of 'Alnico Horseshoe Magnets' - there 
> should be a type number on the original order, if not on the magnet.

I located one receipt - see additional info below.  For the other two, measurements are mine because there is no identifying information available.

> 
>        What were you using brass ball bearings for? Stainless steel is 
> usually used.

I attempted to use a threaded brass rod with a matching brass ball bearing as a boom.  Unfortunately the brass rod was not stiff enough.  Instead, a square aluminimum rod with a steel ball bearing worked fine.

>        Regards,
> 
>        Chris Chapman
> 
> > 
> > (1) PSN-ADC-EQAMP Four-channel Seismic Amplifier/Filter Board
> 
>        How many amplifiers are there on the board?

It's the four-channel (fully-loaded) board so there are four amplifier/filters.  You can simultaneously attach four seismographs.  From the docs:
     Lowpass filter cutoff frequency:  5 Hz
     Highpass filter cutoff frequency:  60 seconds
     Input impedance:  10K
     Gain range with gain jumper installed:  ~160 to 600
     Gain range with gain jumper removed:  ~600 to 8000

> 
> > (1) PSN-ADC-SERIAL 16-Bit Serial Output Analog to Digital Converter Board
> > Note:  Boards mounted together in aluminum enclosure.  Slightly used, fully
> >        operational, excellent condition.
> 
>        Does it have a cable for connecting it to a computer?

Yes.  Includes the wall-wart power supply, serial cable, docs and sale receipt from Larry Cochrane.   I am the original purchaser and owner.

Has WWV Time Correction option, too.

Note:  This hardware originally cost $485 in 2004.  It has been rarely used.  I think a fair price is $300 but will consider other offers, especially if you want the other items as a package.

> 
> > (1) Full spool of 36 ga magnet wire
> 
>        What weight on the spool? They come in many sizes.

One pound.

> 
> > (2) Partial spools of 34 ga magnet wire
> 
>        What weight?

Each was one pound.  I'm guessing about 1/5 to 1/4 remain on the spools.

> 
> > (2) Hand-made coils (using 34 ga wire from partial spools)
> > (3) Alnico horse shoe magnets
> 
>        How many and what sizes?

Two hand-made coils using 3" plastic discs attached to a 1" wood core.  The second turned out much better than the first and fits nicely between the large horse shoe magnet (it was mounted on the boom with an aluminum L-bracket, still attached).  You can reuse the magnet wire from the first coil or fix it, your choice.

Lacking a winder machine, I have no idea what length of wire is on each coil.

Large horse shoe magnet is McMaster-Carr 5841-K14 "Alnico 5 magnet, bridge, 1-1/8" L O'All, 1-3/4" W O'All, 30 lbs pull".

Two identical small horse shoe magnets 7/8" between poles.  Imagine magnet is oriented like an upside-down "U".  1-1/8" high, 1-3/4" wide, 1-1/8" deep.

All three have keep bars and are quite strong.

> 
> > (2) 7-1/2" Turnbuckles
> 
>        How many?

Quanitity 2.

> 
> > (2) Line levels
> 
>        How many?

Quantity 2.   You find these at any hardware store.  One was mounted on the boom and makes leveling it quite convenient.

> 
> > (1) Guitar string, steel
> 
>        What wire diameter / music application?

..017 Plain steel string.  I used one of these along with the turnbuckle to hold the boom up.

> 
> > (5) 4" x 4" copper sheets, varying thicknesses
> 
>        How many and what thicknesses?

Quantity five.  8 oz, 16 oz, 24 oz, 32 oz, 48 oz.  These were from a "sample pack" from onlinemetals.com.

> 
> > (1) 3" x 6" copper sheet, 1/4" thick
> > (1) Pkg of 10 brass ball bearing, 1/4", grade 200
> > (1) Pkg of 50 brass machine screw, pan head, 10-32 thread, 1-1/2" length
> > (1) Pkg of 100 brass flat washer, 10-S
> > (1) Pkg of 100 brass hex machine nut, 10-32 thread
> > (1) Pkg of 50 brass hex machine nut, 3/18-16 thread
> > (1) Pkg of 50 brass flat washer, 24-S
> > (1) Pkg of 100 brass hex machine screw, pan head, 8-32 thread, 1-1/2" length
> > (1) Pkg of 100 brass hex machine screw, pan head, 8-32 thread, 1" length
> > (1) Pkg of 100 brass hex machine screw, pan head, 8-32 thread, 3/4" length
> > (1) Pkg of 100 brass hex machine nut, 8-32 thread
> > (1) Pkg of 100 brass flat washer, 8-S
> 



In a me=
ssage dated 04/08/06, jr_brady@........... writes:



I'm offering the following part=
s for sale to the group.  They were used in

the construction of a Lehman sensor. 

Thank you,

Jason Brady   Lynnwood, WA USA

jr_brady (at) comcast (dot) net




Hi Jason,



       If you would specify the sizes / quanti=
ties outlined below as queries, it would be a great help, please. Otherwise=20=
we don't know what you are trying to sell! 



       There are maybe a dozen sizes of 'Alnic=
o Horseshoe Magnets' - there should be a type number on the original order,=20=
if not on the magnet.



       What were you using brass ball bearings=
 for? Stainless steel is usually used.



       Regards,



       Chris Chapman





(1) PSN-ADC-EQAMP Four-channel Seismic Amplifier/Filter Board



       How many amplifiers are there on the b=
oard?



(1) PSN-ADC-SERIAL 16-Bit Seria=
l Output Analog to Digital Converter Board

Note:  Boards mounted together in aluminum enclosure.  Slightly us=
ed, fully

       operational, excellent condition.



       Does it have a cable for connecting it=
 to a computer?



(1) Full spool of 36 ga magnet=20=
wire




       What weight on the spool? They come in=
 many sizes.



(2) Partial spools of 34 ga mag=
net wire




       What weight?



(2) Hand-made coils (using 34 g=
a wire from partial spools)

(3) Alnico horse shoe magnets




       How many and what sizes?



(2) 7-1/2" Turnbuckles



       How many?



(2) Line levels



       How many?



(1) Guitar string, steel=




       What wire diameter / music application=
?



(5) 4" x 4" copper sheets, vary=
ing thicknesses




       How many and what thicknesses?<=
FONT  COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff"=
 SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">



(1) 3" x 6" copper sheet, 1/4"=20=
thick

(1) Pkg of 10 brass ball bearing, 1/4", grade 200

(1) Pkg of 50 brass machine screw, pan head, 10-32 thread, 1-1/2" length

(1) Pkg of 100 brass flat washer, 10-S

(1) Pkg of 100 brass hex machine nut, 10-32 thread

(1) Pkg of 50 brass hex machine nut, 3/18-16 thread

(1) Pkg of 50 brass flat washer, 24-S

(1) Pkg of 100 brass hex machine screw, pan head, 8-32 thread, 1-1/2" length=


(1) Pkg of 100 brass hex machine screw, pan head, 8-32 thread, 1" length

(1) Pkg of 100 brass hex machine screw, pan head, 8-32 thread, 3/4" length
(1) Pkg of 100 brass hex machine nut, 8-32 thread

(1) Pkg of 100 brass flat washer, 8-S