Excellent Gary,
that is what it is all about, experimenting and testing the theories and =
views expressed, then coming to your own conclusions,
pleae keep it up
regards
Dale
  ----- Original Message -----=20
  From: Gary Lindgren=20
  To: psn-l@.................
  Sent: Friday, July 04, 2008 9:07 AM
  Subject: Tungsten Rods


  I have been taking my time to get my first Lehman up and running. =
First just to learn how the thing works and then to optimize the =
operation. In the last month we have had lots of discussion on various =
Tungsten rods and other materials for the 2 horizontal rods and ball =
bearing support system. I first tried various rod materials by trying to =
get as long resonant period, but came to the conclusion this was =
difficult to repeat. Meredith on his 6/25 message got me thinking to =
take a different approach. I reset the Lehman for a short period (about =
10 seconds) and then connected the sensor to the amplifier and watched =
the display as the amplitude decayed. Now we have something that can be =
easily measured and repeated. I standardized on measurements for 5 =
minutes or 300 seconds. The decay equation is Y=3D A e- t/T where t is =
time and T is the time constant of the system. For materials I used =
hardened steel, stainless steel, tungsten carbide (as received), =
tungsten carbide (mirror polished) 1/8" diameter rods. The ball bearing =
is =BC" diameter silicon carbide.=20

  Here is what I found for the time constants:

  Hardened steel: 154 seconds

  Stainless steel: 125 seconds

  Tungsten carbide ( as received): 155 seconds

  Tungsten carbide (mirror polish): 191 seconds

  =20

  The goal is to have a high time constant, indicating lower friction.

  =20

  Polishing: The tungsten carbide as received actually had a very good =
polish when received, but not quite a mirror finish. I obtained 3 =
diamond polishing grit sizes, starting out with 35u, then 15u, and =
finally 3u. The 35 and 15u actually made the tungsten carbide rod =
rougher. I followed Chris Chapman's method for polishing using a bent =
sheet of copper with the diamond paste.

  =20

  Conclusion: Polished tungsten carbide rods have the lowest friction.

  =20

  =20

  Gary

  =20

  =20

  =20

  =20

  Gary Lindgren

  585 Lincoln Ave

  Palo Alto CA 94301

  =20

  650-326-0655

  =20

  www.blue-eagle-technologies.com

  cymonsplace.blogspot.com=20

  =20

  =20



-------------------------------------------------------------------------=
-----


  No virus found in this incoming message.
  Checked by AVG.=20
  Version: 7.5.524 / Virus Database: 270.4.3 - Release Date: 28/06/2008 =
12:00 AM







Excellent Gary,
that is what it is all about, =
experimenting and=20
testing the theories and views expressed, then coming to your own=20
conclusions,
pleae keep it up
regards
Dale

  
----- Original Message ----- 
  From:=20
  Gary=20
  Lindgren 
  
To: psn-l@.............. 
  
Sent: Friday, July 04, 2008 =
9:07 AM
  
Subject: Tungsten Rods
  


  

  
I have been taking my time to get my first Lehman =
up and=20
  running. First just to learn how the thing works and then to optimize =
the=20
  operation. In the last month we have had lots of discussion on various =

  Tungsten rods and other materials for the 2 horizontal rods and ball =
bearing=20
  support system. I first tried various rod materials by trying to get =
as long=20
  resonant period, but came to the conclusion this was difficult to =
repeat.=20
  Meredith on his 6/25 message got me thinking to take a different =
approach. I=20
  reset the Lehman for a short period (about 10 seconds) and then =
connected the=20
  sensor to the amplifier and watched the display as the amplitude =
decayed. Now=20
  we have something that can be easily measured and repeated. I =
standardized on=20
  measurements for 5 minutes or 300 seconds. The decay equation is Y=3D =
A e- t/T=20
  where t is time and T is the time constant of the system. For =
materials I used=20
  hardened steel, stainless steel, tungsten carbide (as received), =
tungsten=20
  carbide (mirror polished) 1/8=94 diameter rods. The ball bearing is =
=BC=94 diameter=20
  silicon carbide. 
  
Here is what I found for the time =
constants:
  
Hardened steel: 154 seconds
  
Stainless steel: 125 seconds
  
Tungsten carbide ( as received): 155 =
seconds
  
Tungsten carbide (mirror polish): 191=20
seconds
  
 
  
The goal is to have a high time constant, =
indicating lower=20
  friction.
  
 
  
Polishing: The tungsten carbide as received =
actually had a=20
  very good polish when received, but not quite a mirror finish. I =
obtained 3=20
  diamond polishing grit sizes, starting out with 35u, then 15u, and =
finally 3u.=20
  The 35 and 15u actually made the tungsten carbide rod rougher. I =
followed=20
  Chris Chapman=92s method for polishing using a bent sheet of copper =
with the=20
  diamond paste.
  
 
  
Conclusion: Polished tungsten carbide rods have =
the lowest=20
  friction.
  
 
  
 
  
Gary
  
 
  
 
  
 
  
 
  
Gary=20
  Lindgren
  
585=20
  Lincoln Ave
  
Palo=20
  Alto CA 94301
  
 
  
650-326-0655
  
 
  
www.blue-eagle-technologies.com
  
cymonsplace.blogspot.com 
  
 
  
 
  

  


  
No virus found in this incoming message.
Checked by AVG.=20
  
Version: 7.5.524 / Virus Database: 270.4.3 - Release Date: =
28/06/2008=20
  12:00 AM