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Edison Gem Mandrel Pulley Project
Posted: Mon Aug 21, 2023 1:54 pm
by dzavracky
Hey Everyone,
VanEpsFan asked if I could help him make a new pulley for his Edison Gem mandrel. I have never owned a gem (nor do I have any desire to

), so I am not 100% if this came out correct. But it was good practice for me to CAD this out and I'm 99% confident that it will work. I used the old and broken pot metal one to make this 3D printed one.
I don't know if replacements are already available or not, but if anyone could use one of these send me a PM. Also, if anyone could needs a part made and 3D printed let me know! I like having the extra practice with Solidworks and I have access to 3D printers.
Cheers,
David
Re: Edison Gem Mandrel Pulley Project
Posted: Mon Aug 21, 2023 2:04 pm
by VanEpsFan1914
Let me put on a bit of a Paul Harvey moment here. David came visiting about a week ago on the way to the beach, and naturally every still-working phonograph in the house except a VV-IV and a Vivatonal portable got a workout. That was fun.
The Gem doesn't work at all and I had paused my repairs until I could get a new pulley. Casting one from alloys using a wax model and greensand had been about the only option and I have ninety million projects lined up and nowhere to run a crucible.
He's made this using a crumbly original pulley core and the original brass shell of the mandrel, and it looks fantastic.
And now you know The Rest of The Story.
Looks great David and I am very curious to see if I can now get the Gem working.
Replacements aren't available through the usual suppliers. I checked.
This part, if it was sleeved with a piece of brass tubing to act as a plain bearing surface (much better than the old pot metal) would have a crazy long service life but I frankly don't see my keywind Model A Gem getting worn out anytime soon. They don't sound great.
Cute, but they still don't sound great.
Now mine can sound horrible again as nature and Thomas Edison intended.
Charles F
Re: Edison Gem Mandrel Pulley Project
Posted: Mon Aug 21, 2023 2:54 pm
by Curt A
It looks good and way better than pot metal...
Re: Edison Gem Mandrel Pulley Project
Posted: Mon Aug 21, 2023 3:00 pm
by rgordon939
I bought a couple replacement pulleys from Ron Sitko years ago. I wonder if The Phonograph Shop might have some.
Rich Gordon
Re: Edison Gem Mandrel Pulley Project
Posted: Mon Aug 21, 2023 3:08 pm
by VanEpsFan1914
rgordon939 wrote: Mon Aug 21, 2023 3:00 pm
I bought a couple replacement pulleys from Ron Sitko years ago. I wonder if The Phonograph Shop might have some.
Rich Gordon
One Sitko/Parlier part I do recommend is the turned aluminum lower pulley for the Home and Gem Motors.
It is made to more precise dimensions than original parts with over a century of decay and distortion, and does not tarnish. I have used two of them.