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=94 diameter rods. The ball =
bearing is
=BC=94 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=92s
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














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. 

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

 

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

 

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.

 

Conclusion: Polished tungsten carbide rods have the =
lowest
friction.

 

 

Gary

 

 

 

 

Gary Lindgren

585 Lincoln Ave

Palo Alto CA 94301

 

650-326-0655<=
/span>

 

www.blue-eagle-technologies.com

cymonsplace.blogspot.com