[TheForge] forging steel bamboo

[Ben Barrett]

At the last NWBA conference, up in the Columbia River Gorge, there was
a great pipe candleholder demo (by Dave Lisch I think), and they used
a chop-style tool set into the hardie.
It used two pieces of leaf spring, both bolted onto the hardie
shaft... the bottom was along the anvil, and the upper one pivoted
(and could be raised or lowered for different sizes of pipe).  I'm
sure there is a more common name for this, but I've also seen
guillotine tools more or less like the smithin magician used for this.
 I think the main advantages of the chops-style are that it is an
easier tool to build (although the dies must be kept in-line since
they're not guided on both sides), and it might be a little easier to
remove the working piece from the tool.  I just built my first
guillotine, it was more forgiving that I thought, and I like that
different dies can be dropped in rather than switching out the whole
tool, for varying work.  I should also note that the dies I saw were
ground/shaped (off the edges of the leaf spring) a bit, roughly for
the size of the material being worked.

If you've never worked with a guillotine tool before, watch out for
the gremlins, the dies can get jammed in there diagonally if the
tolerances are too great, although you need a bit of leeway to get
things loosened sometimes.  I took the get're-dunn approach and just
clamped some folder paper scraps around the dies between the rails
when I was setting up to weld, and found that was an easy way to shim
to usable tolerance (was about 3-5 layers, a folder envelope scrap).
My buddy Jim motivated me on this tool and suggested just using square
stock, even the same material as the rails, just inside the rails, and
welding the dies to that, so that we don't get screwed up with varying
die sizes and trying to forge them to a precise size to fit in the
rails (most larger leaf spring is much thicker in the middle than at
the ends, along its length).  That gave me some fun ideas about
mounting other tools & odd dies into the guillotine, since I work
along it is a super 3rd and even 4th hand to have around :)

Mark, the gist of it is pinch-and-upset.  Pinch the pipe in an even
ring, and then when you upset that area, it folds itself in on the
ring and tends to bulge just a bit.  If the rings are not even, you
will get really neat organic lumpies that don't look much like bamboo,
so experiment :)  I did some pinching with a straight pein and the
edge of the anvil, and it worked but I was not making even rings.
This generally works best on thick-walled pipe, but I'm sure it could
be finessed into thinner material.
I found a video with a quick google search, of a guy making metal
bamboo -- he uses some sort of fuller-tongs thingy instead of a
chop-style or guillotine (no hammer blows to pinch), then upsets the
piece after quenching all but the pinched area.

cheers, folks!  Oh and I concur, nice work Kirsten!

ben


On 10/26/07, Bruce Freeman <FREEMAB at pt.fdah.com> wrote:
> How much do you need to maneuver the pipe in this process?
> Would a lightweight overhead crane (simple jib-type crane with a truck) do the trick to take the load off you?
> Such a crane, wall-mounted or pole-mounted, is easily constructed and mounted.
>
> Bruce
> NJ
>
>
> >>> "Fiorini & Skiles" <bkmetal at mwt.net> 10/26/2007 6:52 AM >>>
>
> <snip>
>  I got to the point where I could manage
> a 5 ft long length of 7/8 pipe on my own, but anything heavier is too much
> for me to manuever.
> <snip>
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