metal spinning

[acewoodturner]

I have a commission coming up for a whisky company which part of it requires a small metal hemispherical dish with a diameter of 40mm and a 10mm lip around the edge and to be made out of copper. I have searched online but have been unable to buy one. I have thought of a couple of different ways to make one. I could make a positive and negative former and heat treat the copper and then using the formers in a bearing press, I could press them out. I could also make a negative hole in a piece of end grain oak and then pein it gently and then polish it up. Then there is the metal spinning method. Not much info out there on the diy method. I seem to remember Robert Sorby doing metal spinning kits with pewter a few years ago but there is nothing on their website now. If I can successfully make these three samples there will be some big orders coming in. It might be worthwhile then to get a quote from a metal pressing company. Until then I think it is up to me to make them. Does anyone have any advice regarding making them or even know of diy kits to get me started. Even better does anyone know if I can buy them off the shelf?

Thanks in advance for any help.
Mike

 

[jasonB]

At that size its quite easy to spin, just make a wooden former to go in the chuck and sandwich in a disc of copper between a wooden pressure plate with the tailstock and then use your rest with a pin in it to lever a spinning tool against. Only needs to be a bit of polished steel or ball bearing welded to the end of a shaft. The part laying down is a similar sized thing I did in 0.8mm steel.

 

[srp]

Used to work at a metal spinning company - saucepans, light fittings, parabolic reflectors etc, and mostly aluminium. The metal spinning lathes were heavily built, with massive bearings in the headstock as the forces involved are considerably higher than for conventional wood, or even metal, turning.
For a few small items though, a normal lathe (wood or metal) will be man enough. Most of the tools used had the business end shaped like the back of a spoon, and were highly polished. Tallow was used to prevent dragging and pick-up. The metal will work-harden during spinning, so you might need to anneal it once or twice during the spinning process (for copper, heat to red heat and quench in water ).
There are a few Youtube videos on spinning that might help to get you started if you haven't done any before.