Re: how to spin metal

From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Sunday, November 30, 1997 6:59 AM
To: 	Tesla List
Subject: 	Re: how to spin metal

On Sunday, November 30, 1997 2:33 PM Antonio Carlos M. de Queiroz
[SMTP:acmq-at-compuland-dot-com.br] wrote;

> Alfred A. Skrocki wrote:
> > Now I know you guys didn't know what you were doing! There is NO reason to
> > weld a toroid if properly spun. The seam is rolled into itself and is
> > barely visable. If you needed to sand the finished toroid you DIDN'T use
> > enough lubrication while spinning. For Aluminum or copper you should use a
> > lot of tallow or soap to lubricate your tools and then you get an almost
> > mirror finish just from the spinning, actually it looks like a wire brushed
> > finish.
> After reading what I could find in the WWW and thinking about what I can do
> with the tools that I have, I am imagining the following procedure:
> I would first cut in the lathe a cylindric wood block with the section of a 
> "negative half-toroid":
>     _   _|_   _
>    | \_/ | \_/ |
>    ------+------ 
>          |
> The block would be bolted to a headstock plate. Next, I would bolt to the
> center of the block a circular sheet of aluminum or brass, or simply press it
> there with the tailstock, and do the spinning by pressing it against the wood 
> block with adequate tools (rollers?).

Basicaly so far so good except you don't screw the aluminum onto the form 
but hold it there with a wooden ball screwed into the lathe's tailstock.

> After trimming the excess in the borders, I would have a half-toroid with
> the hole closed by a flat plate. Two of these would make a toroid.
> Can you give details on how to make the seam?

You would now move the aluminum to another wood form that is internally 
sectional and it allows you to roll the semi-donut almost back on itself 
then you would move to a wooden former that only held the center disk of 
the toroid and completely roll the donut into itself thus forming a 
pressure tight seam. You'll surelly screw up the first three or four before 
you get the hang of it.

> I am not sure if I will really try to do it, because my lathe can't cut large
> pieces (is a 18 cm toroid useful?), and the lubricant would make a mess in 
> all my workshop...

I learned to either use a beefed up faceplate lathe or make my own lathe.
The tools are all bulbous in shape and are used with a manual tool post 
holder that has verticle steel pins to lever against when shaping the 
metal. The lubrican isn't as much of a problem as you might think, the 
tallow is of a consistancy of thick grease and if you use soap you just 
hold the edge of a bar of soap aqainst the metal. BTW if you use soap use 
an olive oil based soap it has the best lubricating characteristics.


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                           Alfred A. Skrocki
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