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Re: [TCML] Large Top Loads



Jim,

I think i estimated the weight at some point to be around 15 lbs based on
all the materials used.  Its not much heavier than the toroid it replaced,
which was made from black corrugated plastic tube wrapped with duct tape and
foil tape, with a 1/4" plywood center disk.

I added the 4 extra spacers because i was not happy that there was a slight
non-parallel aspect to the rings, due to the cork-screw effect i talked
about before.  If you could bend the rings perfectly so they lay flat, then
you may be fine with less supports.  I thought the 8 supports made it look
better anyway (either have no visible supports, or lots of them).

Steve

On Mon, Feb 15, 2010 at 8:54 PM, James Zimmerschied <zimtesla@xxxxxxx>wrote:

> Steve,
> thanks for the great pictures. It encourages me to give it a try. How much
> do you estimate it weighs? Also it looks like you were adding more web
> spacers in the last photo. Were the original four not enough?
> Jim
>   ----- Original Message -----
>  From: Steve Ward<mailto:steve.ward@xxxxxxxxx>
>  To: Tesla Coil Mailing List<mailto:tesla@xxxxxxxxxx>
>   Sent: Monday, February 15, 2010 10:14 AM
>  Subject: Re: [TCML] Large Top Loads
>
>
>   It was some work, but yes, it can be done:
>
>   http://stevehv.4hv.org/ringtoroid/<http://stevehv.4hv.org/ringtoroid/>
>
>  The harbor freight bender needed some mods right from the get go.  I added
>  some 1/16" thick HDPE shims to keep the rollers from being able to move
>  laterally.  Even with this, its best to have a second person guiding the
>  tubing in real straight.  Its easy to get a slight cork-screw if your
> guider
>  isnt really on the ball.  A real tube bender would have up-right rollers
> to
>  keep the tube feeding in true.
>
>  I used some short pieces of 3/4" PVC as it fit super snug into the 1" OD
> AL
>  tube to join the ends.  The AL tube was .065" wall thickness.  Id suggest
>  buying at least one more tube than you need so you have 1 piece to get the
>  learning aspects out on.  The last picture shows the toroid how it really
>  ended up, with 8 supports and huge zip-ties to snugly hold all the rings
> in
>  shape.  Because my rings were slightly cork-screwed, they did not want to
>  sit perfectly, hence the need for more supports and the ties to hold them
> in
>  shape.  Certainly the next time through would give less problems.
>
>  Also note that the bender produces scrap at each end of the ring, about 6"
>  worth of material that cannot be bent.  So if you really want to get a 48"
>  toroid, you will probably have to get a few 20' lengths of tube, and the
>  rest could be 12' lengths.
>
>  The only other tool i used in my friends machine shop was the bandsaw to
> cut
>  the ends of the tube square.  This can be done with a hack-saw and some
>  patience if you dont happen to have access to a giant metal cutting saw
> :-).
>
>   http://www.teslauniverse.com/community/groups/ratcb#num=206&id=album-11<
> http://www.teslauniverse.com/community/groups/ratcb#num=206&id=album-11>
>
>  That link should point to some photos from the 2009 teslathon with
> operating
>  pictures of that toroid.  I'd say it works.
>
>  Steve
>
>   On Mon, Feb 15, 2010 at 10:05 AM, David Speck <Dave@xxxxxxxxxxxxxxxx
> <mailto:Dave@xxxxxxxxxxxxxxxx>> wrote:
>
>  > Jim,
>  >
>  > If you look in the back of Smithsonian, Discover, or Air and Space
>  > Magazine, you will often find a Harbor Freight ad good for 20% off any
>  > purchase.  A friend bought one of those rollers a few months ago.  Seems
>  > well built.
>  >
>  > I'm going to try using ~1" diameter rigid coax that I bought at a
> hamfest
>  > for next to nothing.  If I remove the outer PVC jacket, I'll have a nice
>  > corrugated copper tube for the toroid segments.  Probably will be a bit
>  > heavier than aluminum, though.  Just need time to try out the concept.
>  >  Aluminum tube is crazy expensive around here, unless you can find it
>  > surplus somewhere.
>  >
>  > Steve Ward made his beautiful toroid with a Harbor Freight bender.
>  >
>  > Dave
>  >
>  >  Harbor Freight has a  manually driven version for about $150. [Not sure
> if
>  >> it
>  >> could actually roll a 48" diameter x 1" aluminum tube.]  My question
> is:
>  >> has
>  >> anyone tried to fabricate a top load made of a cluster of aluminum
> tubing?
>  >>
>  >> Thanks,
>  >> Jim Zimmerschied
>  >>
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