[TheForge] Bending steel

[Bruce Freeman]

So the maximum chord would be 5" on a 3' sphere.  That's 1/22th of the
circumference.  Any arc smaller than about 1/20 is indistinguishable
from a chord.

Hence, it's not worth doing a compound curve, unless you need the
added strength.

So make yourself a wooden mandrel (or half-mandrel) just under 3' in
diameter (to allow for spring-back), and bend the material cold over
this  Once you've assembled the thing, round the outer edges a trifle
for eye-appeal.

On Mon, Feb 23, 2009 at 8:34 PM, Mark Novak <mark at fireworkspdx.com> wrote:
> I'm planning on cutting 1/8" sheet into irregular strips, likely 4-5"
> at widest, and then bending them and making them convex enough to
> ultimately come to a 3-4' sphere (though it will not be a complete
> sphere - there will be intentional gaps so that the object suspended
> in the middle of the sphere will be plainly visible).
>
> I'm considering making a jig (like the large bowl of my swage block)
> that I can hammer it into hot, though I know there will be dents and
> distortion without some uniform press die... I'm hoping what ends up
> visible from the outside will either grind out or be attractive. :)
>
> Since I have a tiny shop without any power hammers or presses, I'm
> hoping I can accomplish this with hand power or some jury-rigged press
> (thoughts on that?).  Thanks for your advice! Keep it coming, please.
>
> Mark
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-- 
Bruce
NJ

The total lack of evidence is the surest sign that the conspiracy is working.