I am interested in learning how to use a metal lathe to spin
bowls and other vessels. I have access to a spinning lathe but I
have no idea how to use it. I thought I had found someone who
might teach or even refer me to some but when I
asked, her response was “When hell freezes over!”. I don’t
think that avenue has too much promise… If anyone knows
anything about metal spinning lathes and is willing to relay it
to me I would be immensely grateful… Thank you so much<<
I have some experience in spinning techniques which you may find
useful in your quest to do some metal spinning. 1. Make sure you
have the right lathe for the job: In my experience it is
difficult to do spinning satisfactorily on a metal turning lathe
because of the restrictions of size between the lathe bed and the
chuck centre. If you have a large wood turning lathe that is
fine. You need enough swing between the centre of the chuck
and the bed of the lathe to accommodate the wooden formers used
for spinning and the disks of metal. The lathe should have just a
toolpost with several holes in it so a toolrest can be moved up
or down the holes easily and quickly.
-
The spinning former. The spinning former should be made from a
suitable hardwood, boxwood or lignum vitea is ideal. Softwoods
are not suitable. Make sure that there are not any “returns” on
the former i.e. that the former will not get trapped inside the
metal form when the spinning operation is finished. If you do
want to spin forms that get narrower towards the top you will
have to section the wooden former with a removable centre, quite
tricky! The formers should be well finished because all the marks
on the former will show on the metal. -
Getting the spinning form on the lathe. You can either use a
back plate and screw the formers onto, or better still thread
the back of the former and screw it directly onto the lathe
spindle. -
Getting ready to spin the work. The lathe should have several
speeds. fairly slow to a bit faster. Fast speeds are very
dangerous because the work can fly off the lathe with disastrous
results. A revolving centre should be used in the tailstock with
a wooden friction unit. A fairly small turned piece of hardwood
wood with a deep recess in the back to take the revolving centre
is used to clamp the work (metal disk) to the wooden former. The
metal disk is placed fairly centrally between the wooden former
and the friction unit. Some pressure is applied the revolving
centre by the tailstock. Start the lathe at a slow speed and
release the pressure very slightly with the tailstock. The disk
of metal can be centred (be very careful) with a spinning tool
by gently pressing the tool against the edge of the metal disk
until it is centred. The actual metal forming is done with an
annealed circle of metal, copper silver etc. So make sure that is
done first. Spinning tools. They are basically like oversized
burnishers, about the size of wood turning tools. The need to
have a highly polished rounded end, various shapes can be used
for different work. The side of the spinning tool (about a third
from the working end) is pressed against the toolrest, then use
your own body weight to lever the spinning tool against the
metal disk easing the disk over the wooden former. -
Spinning the work. Using your chosen spinning tool, and after
centering the work, apply some grease to the metal disk to act as
a lubricant, very gently apply some spinning tool pressure to a
position fairly near the centre of the metal disk. Ease the tool
towards the edge of the disk applying sufficient pressure so
that disk begins to dish slightly. You can repeat this several
times until there is a noticeable dishing in the metal disk.
There may come a time when the disk seems be getting harder. You
will probably have to anneal it at this stage. You may well have
to anneal the work several times during the course of the
spinning operation. Apply more grease when the disk has been
annealed and put back on the lathe. Repeat the forming process
with the spinning tool. You may be able to apply more pressure
progessively as the work goes on. If you apply to much pressure
the metal will start to buckle. Keep repeating the process until
the metal dick takes on the shape of the wooden former. When
this is achieved, it may be possible to polish the formed shape
with the spinning tool against the wooden former. When finished
remove the wooden former from the lathe any take it out of the
metal shape. Success!!
Hope that helps.
Richard.
Richard Whitehouse,
Silversmith,
Ardleigh Workshop,
Ardleigh,
Colchester,
UK