In a message dated 16/06/2007 22:13:22 GMT Daylight Time, Paulc@........  
writes:

Chris,
I have changed from the ball bearing, with  wire suspension to crossed 
cylinders for both the top and bottom bearing  surfaces.
The wire suspension seems to cause noise  when ever the the frame was touched.
I wanted to get rid of the resonance of  the wire so both the horizontal 
boom, and the suspension are now  tubes.
No more rotational problem around the  horizontal mass axis either.
The last step was building the interface  between the tubular suspension and 
the vertical support, so I could use the  crossed cylinders there as well.



Hi Paul,
 
    Sounds fine. The cylinders on the vertical support  should be vertical. 
The arm carries the horizontal cylinders. This makes set up  and operation much 
easier. You can buy solid tungsten carbide drills up to 1/8".  The McMaster 
Carr pins are what John Cole uses.
 
    Twin tubes should give a rigid suspension. To  get good performance out 
of a V suspension, the cable need to be fairly heavy.  You just use the fine 
piano wire for the top 1/2".
 
    Regards,
 
    Chris Chapman



   






In a message dated 16/06/2007 22:13:22 GMT Daylight Time, Paulc@........
t=20
writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
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Chris,
  
I have changed from the ball bearing=
, with=20
  wire suspension to crossed cylinders for both the top and bottom bearing=20
  surfaces.
  
The wire suspension seems to cause n=
oise=20
  when ever the the frame was touched.
  
I wanted to get rid of the resonance=
 of=20
  the wire so both the horizontal boom, and the suspension are now=20
  tubes.
  
No more rotational problem around th=
e=20
  horizontal mass axis either.
  
The last step was building the inter=
face=20
  between the tubular suspension and the vertical support, so I could use th=
e=20
  crossed cylinders there as well.

Hi Paul,
 
    Sounds fine. The cylinders on the vertical supp=
ort=20
should be vertical. The arm carries the horizontal cylinders. This makes set=
 up=20
and operation much easier. You can buy solid tungsten carbide drills up to 1=
/8".=20
The McMaster Carr pins are what John Cole uses.
 
    Twin tubes should give a rigid suspension.=
 To=20
get good performance out of a V suspension, the cable need to be fairly heav=
y.=20
You just use the fine piano wire for the top 1/2".
 
    Regards,
 
    Chris Chapman