With bad pivot bearings.
If appears to be impossible to find bearings or any general information on the tonearm.
This is the lower pivot bearing on which everything rides. It appears to be close to .180" which would be 3/16" and is a fine thread pitch. Somewhere we have thread measuring guides.
The center hole (that has blown out) appears to be around .0610 which would be close to 1/16 inch.
In the bottom of the hole it looks like there is a bearing, perhaps a small ball, but it is jammed in tight and I can't really tell.
There is also a small pivot pin which has broken off on the other side of the bearing mount. The pin is 1/16th I think.
It is sort of hard to explain.
But I did a lot of measuring and made my usual indecipherable notes.
I'm going to attempt to find out the thread pitch and then drill out a set screw. Drop a 3/16" ball bearing into the hole with a little oil to make it stick and cut off a drill bit to make a hardened pin.
The center section I think I can machine out of bar stock and also drill out the ends to accept a pin. I'll put another ball bearing into this support post.
I do not have a jeweler's lathe so I suspect that drilling the tiny hold will be hard to do with the big shop lathe.
I should find the research shop at my College. I've heard they don't let groundskeepers near precision tooling. But it may just be me.
Somewhere there is a repository of Fairchild Tonearm parts which someone is probably going to throw in a dumpster because they have no idea what they are.
I of course really have no business playing with something like this. There are probably only a handful left in the world.
But it looks so cool with my vintage Rek-o-Kut turntable...
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I have in my Dad's tool chest a Thread file. It is a square shaft with different count thread files on four sides and both ends. So it has 8 different thread files that works well to determine what threads I am working with as well as cleaning up threads.
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