Spinning aluminium diaphragm

[chunnybh]

Hello,
Does anyone know the method of spinning diaphragms?. I hear they are far superior to pressed type. I have tried pressing them and find they always wrinkle at the edges.
Thanks

[Guest]

Spinning the diaphragms to be made seems to br better than cold pressing. George Overstall's diaphragm making equipment is with Paul Morris in Exeter. I hope to obtain it back sometime to make my own diaphragms. A lathe is essential to the diaphragms manufacture, and the heat evolved in producing them seems to temper the metal to it's advantage.

[chunnybh]

Can you please write a quick discription of the method and formers.
Thanks

[old country chemist]

Hello chunny, well, I cannot describe the items fully for making the diaphragms, but there is a male mould and a female mould-one fits inside the other when the aluminium is compressed in the lathe. Some heat is formed, which seems to improve the diaphragms. The only real problem is when you come to part the finished item from the male part in the lathe. It must be done with a special sort of parting knife, and as I have not seen the equipment for several years, I cannot fully describe or photograph the equipment for you, but I will do so when I get it all back, including a roll of the aluminium foil, of which seems to be the correct thickness for the job.

[GMEMG]

I seem to recall some sort of guide or istructions on how to spin metal diaphragms in one of the Talking Machine News or Soundwave magazines - Roger thorne had complete sets of these ..........

Sadly they have vanished since his Death

Someone must have them - they would certainly help