"williamhenry" wrote in message
...
regardless of the shape internally , you could machine this part on a
lathe
, with little trouble , the internal taper is a little tricky but not
really

how many do you need?

what is it worth /

have you tried getting prices from machine shops?


I have put a ball bearing set-up in a lathe, similiar to a single wheel
knurling tool to roll thin material into shapes. The idea of reducing the
dia. of tube may not work out to well. How about starting with the 1/2"
tube, and plug the ends, then introduce air pressure in the tube and
carefully heat it in the section you want expanded? I did this with an
expansion chamber that was smashed almost flat and the results were way
better than I expected. Low pressure and more heat is probably the safest.

Dixon