I managed to spin a cover for one side of the RH exhaust silencer I am using, ruined three others. Anyone tell me two things:
What lubrication do you use for spinning aluminium?
How polished does the ball tool have to be that you spin with?
I guess a lot is down to practice but tried both grease and soap with not much improvement.
exhaust5
exhaust6
exhaust7
The second picture is the former I used and is of 5 inch diameter with a recess for the exhaust pipe.
Cheers
Adrian
[Edited on 26-7-09 by AdrianH]
This guy makes it look easy 
link
[Edited on 26/7/09 by Bigheppy]
Last time I saw it demonstrated, the bloke had a small very shiny wheel fixed in the end of a very long steel bar. The wheel rotated against the metal, transferring the 'push' to the material without friction (not much, anyway).
I just did another using slide way oil, not much improvement.
I saw a guy on Youtube doing small pieces with basically a rounded end on a long bar, every now and then he would seem to wipe the metal with
something.
Using a small disk could be a bit hard to fabricate with the small areas I am working in
I think that I need to use a hardened steel ball highly polished, wondering if a ball bearing could be welded to the end of a rod and then
re-tempered.
Adrian
[Edited on 26-7-09 by AdrianH]
As with so many things, when demonstrated by a competent person, it looks simple.
I can imagine making a most interesting heap of bendy scrap!
quote:
Originally posted by AdrianH
I think that I need to use a hardened steel ball highly polished, wondering if a ball bearing could be welded to the end of a rod and then re-tempered.
[Edited on 26-7-09 by AdrianH]
Tallow used to be preferred. It prevents any oxidation as well as lubricates. The big spinnings are much easier than small things like you are doing.
Make sure your aluminium is well annealed before you start, if you are tearing at the same point in each attempt, stop and re anneal the workpiece,
on tight curves you will work harden the ally very quickly. As for tools as long as they are highly polished where they hit the workpiece they should
be OK. The one you have finished looks pretty good!
caber
Thanks for the responses, I have case hardening compound somewhere to use on my mild steel bars.
I also found a pdf on metal spinning and have just saved that. One thing that dawned on me is I am using half hard aluminium sheet, left over from
body panels, so guess it would be a bit more difficult and could have probably done with heating first.
I am pleased to have done two pieces for the exhaust, Not fantastic but OK for now. I will have to have another play sometime and see what I need to
make for myself.
Cheers
Adrian
[Edited on 26-7-09 by AdrianH]