?I'd trying to construct a 6 foot vertical pole, where a horizontal bar (3
foot wide)
will fall due to gravity and spin around the pole on its way down

a bit like this toy works here.
http://www.vectis.co.uk/AuctionImages/43/2102_l.jpg

Any ideas how I can make such a thing?
TIA
--
Vass

On Aug 26, 2:55*pm, "Vass" wrote:
?I'd trying to construct a 6 foot vertical pole, where a horizontal bar (3
foot wide)
will fall due to gravity and spin around the pole on its way down

a bit like this toy works here.http://www.vectis.co.uk/AuctionImages/43/2102_l.jpg

Any ideas how I can make such a thing?

Scale up the example illustrated. Keep the "screw thread" small in
diameter, thus keeping the helix angle steep and avoiding sticking.

You probably need to make this by bending a helix in tube. This is
often done by bending several helices in parallel, and so self-spacing
them. You might be able to bend three 1/3rd lengths, then joining them
end to end, thus giving three times the pitch of a close-spaced
helix.

I wouldn't assume the helical rod will stay as a rod, but will
probably need to have intermittent mounts from the back. So your
carrier bar needs to have a ring around the upright and just rest on
the helix, rather than having a hole that fits over the helix.


Another way would be to machine it from plastic tube, using a home
constructed "router lathe" (search for that). This is a constructed
square gutter, with a router sliding across the top on a carriage. The
router carriage is driven on 1/2" threaded rod, which is driven by
Meccano chains & gears from the rotating workpiece.


If it's for long term public art, just pay the money and have one
machine bent in stainless tube.

On Fri, 26 Aug 2011 14:55:04 +0100, Vass wrote:

?I'd trying to construct a 6 foot vertical pole, where a horizontal bar
(3 foot wide)
will fall due to gravity and spin around the pole on its way down

a bit like this toy works here.
http://www.vectis.co.uk/AuctionImages/43/2102_l.jpg

Any ideas how I can make such a thing? TIA

How heavy will the horizontal bar be? Unless it's really heavy, I imagine
copying the toy will work - use a form made from wood with protruding
nails at regular intervals and wind a thick bit of steel wire around it
(heating as you go). I think there should be enough tension in the wire
once it's cooled that you can transfer it to a 'fresh' pole and use it as
a guide for the horizontal bar.