On 13 Nov 2005 04:48:35 -0800, wrote:

G'day Rob

I wear very large " L " plates for metalworking so my ideas may not
be practical.

Using some standard brass 3/4" pipe, I want to resize portions of it
down to 1/2", similar to this shape:

http://devnull.dtcc.edu/gfx/shape.jpg

The internal swelling is the hard part and I think it would have
to be made in two parts and joined.

If I were making it, I would turn a mandrel of the internal shape
and then roll sheet brass around the mandrel in two parts, soldering /
brazing each half at the join, removing from mandrel and then joining
both halves together. If you have no lathe, I am sure one of the
members would be able to make a mandrel for you. I have insufficient
skill at lathe operating as I find it hard to get a smooth surface to
my work and postage from Oz would be expensive.

The brass sheet would need to be annealed to make it easier to work.

Other members of this newsgroup are far more experienced than I am and
will, I am sure, have better suggestions, or improvements to my idea.

HTH



Alan
in beautiful Golden Bay, Western Oz, South 32.25.42, East 115.45.44 GMT+8
VK6 YAB ICQ 6581610 to reply, change oz to au in address