In a message dated 08/11/2007, PETERS_RD@.......... writes:

Since  the VolksMeter uses tungsten carbide to establish the axis, I should 
have  thought of the following a long time ago.
A key to reducing  rolling friction is to work with hard surfaces.  Another 
key to reducing  friction in general (if possible) is to reduce the normal 
force.  Both  are achievable by hanging a pendulum from a rare earth magnet, using 
the  ferrous property of the tungsten carbide.
Hi Randall,
 
    Stainless Steel ball bearings are available in a  wide range of sizes. 
_www.smallparts.com_ (http://www.smallparts.com)   They are martensitic Chrome 
steel and are strongly magnetic. SS martensitic rod  is also readily available. 
It might be worth considering mounting the balls in  mild steel with a magnet 
bridge and attaching them to a hardened SS rod. The  magnetic flux would then 
pass from the magnet, through the mild steel to the  balls, across the 
suspension contacts to the circular rod and then through  it.
      
I am uncertain whether the strong permanent  magnetism which will be induced 
near the contact point will add to the dynamic  loss. The relatively low net 
load should decrease the loss.
    It should be quite practicable to extend this to  crossed cylinder 
suspensions. I would expect the magnetic attraction to be  greater for the same 
diameter. 

 
    The dynamic loss does depend on the bearing type.  Previous experiments 
have shown decreasing loss in the series single wires  and foils, crossed wires 
and foils, ball on a plane, crossed cylinders, rolling  wires and foils. 
These rolling systems use a figure of 8 loops around  two circular cylinders. They 
show ~zero rolling force. Ball on a plane and  cylindrical systems may be 
made self centring by curving the plane / providing a  circular support. The 
choice of system may depend on whether the arm needs to be  permanently attached 
to the support structure.
 
    Regards,
 
    Chris Chapman
 







   





In a message dated 08/11/2007, PETERS_RD@.......... writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Since=20
  the VolksMeter uses tungsten carbide to establish the axis, I should have=20
  thought of the following a long time ago.
   A key to reducin=
g=20
  rolling friction is to work with hard surfaces.  Another key to reduc=
ing=20
  friction in general (if possible) is to reduce the normal force.  Bot=
h=20
  are achievable by hanging a pendulum from a rare earth magnet, using the=20
  ferrous property of the tungsten carbide.
Hi Randall,
 
    Stainless Steel ball bearings are available in=20=
a=20
wide range of sizes. www.smallparts.co=
m=20
They are martensitic Chrome steel and are strongly magnetic. SS martensitic=20=
rod=20
is also readily available. It might be worth considering mounting the balls=20=
in=20
mild steel with a magnet bridge and attaching them to a hardened SS rod. The=
=20
magnetic flux would then pass from the magnet, through the mild steel to the=
=20
balls, across the suspension contacts to the circular rod and then through=20
it.
    =20
    I am uncertain whether the strong permanent=20
magnetism which will be induced near the contact point will add to the dynam=
ic=20
loss. The relatively low net load should decrease the loss.
    It should be quite practicable to extend this t=
o=20
crossed cylinder suspensions. I would expect the magnetic attraction to be=20
greater for the same diameter. 
 
    The dynamic loss does depend on the bearing typ=
e.=20
Previous experiments have shown decreasing loss in the series single wi=
res=20
and foils, crossed wires and foils, ball on a plane, crossed cylinders, roll=
ing=20
wires and foils. These rolling systems use a figure of 8 loops aro=
und=20
two circular cylinders. They show ~zero rolling force. Ball on a plane and=20
cylindrical systems may be made self centring by curving the plane / providi=
ng a=20
circular support. The choice of system may depend on whether the arm needs t=
o be=20
permanently attached to the support structure.
 
    Regards,
 
    Chris Chapman