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wsolurb ( Doug Goncz ) wrote in message ...
From: Trevor Jones

There are machines used to swage the
tapers into chair and table legs.

You can make ONE metal part the hard way over a form, and braze it. Make it
niiiiice inside. Then put it in a tall container and fill all round with
concrete or mortar. Then you can roll your blanks up on a regular sheet roller,
press them into the "mold" and tack inside in two places with a stick welder.

Then, if you braze, file, and polish the outside, they'll look slick.
Stainless can be matched with the righ braze filler.

Another way to do it is to have a resilient base matched to the weight of a
large flat bottomed object which presses a tapered form into the sheet. With
the right distribution of weight and "give", you can roll the taper. You'll
have to deal with sprindback, but that's super easy: just make the small end of
the form a little long...

Something like a Vlier pad (several layers of inner tube butyl rubber from the
junkyard) is cheap and adjustable. The weight can be something like an anvil.

Yours,

Doug Goncz, Replikon Research, Seven Corners, VA
Unequal distribution of apoptotic factors regulates
embryonic neuronal stem cell proliferation

I saw a method when I was in Jr High school. It is called explosive
forming.
I don't have an idea of how big these tubes are but this is how I
would try it.
Machine a long bar with the taper inside of it. Mybe you might split a
solid bar first . Then thread the outside of it and put nuts on the
outside.
Then machine the tapper inside . next on the big small end make a
manderal that will fit inside of the tube your are going to taper. On
the big end of the tube make another manderal that fits on the Id of
the tube. Put silicon sealer on the manderal and the tube to make it
water tight. The tube is going to fit tight on the od on the small
tapered end and fit loose on the big taperd end. On the big tapered
end of the manderal drill the manderal to fit in a 45 cal blank shell.
then screw in a bolt about 4 times diamiter deep. Drill a hole for a
firing pin to strike the percussion cap on the 45 blank. Get a wait to
drop form a pulley and take the end of the cord and supend over the
firing pin. Get back behind somthing big and let her drop.It should
work. Make sure that the firing pin has a bigger dia than the hole so
it doesnot fire out of the bolt and act like a bullet. It might take
two or three forming attempts. If your tubes are long you might have
to take this set up out and put in blasing caps to form the tapered
tubs but that is a high vilocity blast and it might crack the tube.
give it a try and email me back how well it works.