On Sun, 11 Nov 2007 10:55:30 +0000, David Billington
wrote:

Prometheus wrote:
On Sat, 03 Nov 2007 22:53:00 -0700, Buy_Sell
wrote:


Anyone spinning metal? I just got these DVDs and thought that they
were excellent.
http://www.metalspinningworkshop.com/


I have the tooling for it, and have tried it a few times, but it's not
as easy as you'd hope, at least with drag tools on a wood lathe.

What ever is.
The main problem I have had is with scalloping on the outside edges as
the part is being formed. Recently, someone posted a video on You
Tube that showed it being done, and it appears that the resolution to
this might be to have a secondary roller behind the blank that keeps
the metal from doing this- but I haven't had the time to try that out
yet.

IIRC the scalloping is due to trying to move the material too far in any
one pass, it can also be a problem with thin material where the blank is
large in comparison to the thickness. I both cases the problem can be
prevented, hopefully, by using a back stick, basically a wooden stick
held on the back of the part to oppose the spinning tool. The back
stick I normally use is about 1" square maple and tapered one end to
get better access as the blank nears the chuck. It is recommended that
it be held underneath the spinning rest which works for me.

I'll give that a try- I've got all the 1" maple rips I could ever
want, and that sounds a lot easier than trying to rig up some kind of
spring roller on the backside.

If you're using drag tools, make sure they're smooth and
mirror-polished, and then make them smoother. That'll work good for
copper and brass, but I've never got aluminum to turn out without
galling.


If you're getting galling is is most likely due to letting the lubricant
film get removed. You need to keep moving and if the lubricant gets
removed in any area then apply more, aluminium galls very easily in my
experience.

Mine too. Maybe I'll try out tallow or lard one of these days, and
see how that treats me.

Best bet is probably to make roller tools- I'm sure there are guys who
can make good parts with the old drag tools, but it's not easy.

Roller tools seem to be used for larger work as they reduce the effort
involved. If you are not getting the results with drag tools that would
suggest you need to refine the technique and practice. Good tips
available at the forum the OP posted.

Definately need more practice to do it well- but there just never seem
to be enough hours in the day. Could be my tools as well- I forged
them myself out of 1018 bar stock, and just guessed at which profiles
might be useful. They work, as far as it goes, but I'm obviously
missing a few things that are probably second-nature to a good
spinner.

OTOH, I found that coppersmithing with a tiny ball-peen hammer and
temporary hardwood swage block is about as easy as it gets. Not
nearly as smooth as a spun part, but sometimes the hammer marks add
enough sparkle to make boring stuff look sharper than it has any right
to.