Tinfoil Phonograph mandrel question

[oceanlinerfanatic]

Do tinfoil machines need a threaded mandrel to work? I know many have one to help with the grooves but is it absolutely necessary to get any sound back?

[TinfoilPhono]

Yes, it must be grooved so that the stylus can push the sound impression into the soft foil. Unlike conventional cylinders, the sound is impressed, not engraved -- a key difference.

There were original attempts to cover a solid mandrel with felt, which offers at least some freedom of the motion for the stylus, but the results were poor.

It perhaps goes without saying that the threading of the mandrel must match that of the drive shaft.

[oceanlinerfanatic]

Yes, it must be grooved so that the stylus can push the sound impression into the soft foil. Unlike conventional cylinders, the sound is impressed, not engraved -- a key difference.

There were original attempts to cover a solid mandrel with felt, which offers at least some freedom of the motion for the stylus, but the results were poor.

It perhaps goes without saying that the threading of the mandrel must match that of the drive shaft.

Thank you Rene! I dont have the tech or knowledge to thread the mandrel so I will try the felt method.

[tim w]

Hello. I wonder if I can make a suggestion ? You could coat the mandrel with paraffin or beeswax then shave it true and smooth. I imagine you will have this attached to a lead screw. Then you could use a stationary scribe tool to cut a groove while the mandrel is being turned. Let the lead screw do the work of spacing it correctly. If it doesn't go right the first time, it would be easy to resurface it and try again. Or this may give you an idea of using some other easily worked materials. Go to the hardware store looking for odds & ends that you can adapt to your purpose. When I was in sixth grade I attempted to make a tinfoil phono unsuccessfully. Maybe I'll give it another go. Good luck.