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NOS Edison Standard mandrel bearing

Posted: Wed Sep 27, 2017 8:13 pm
by Yamaphone
I've had this part for some time and it appears to be a replacement mandrel shaft bearing for a Standard model C,D,E,F &G. I have seen the number on the tag listed on an Edison parts diagram. I always thought that the shaft bearing was just a plain solid cylinder type but this one is different. The main difference is that the center part of the outside has a rounded shape allowing it to roll around a bit if necessary to adjust to any misalignment. The set screw/oil plug holds it in the housing. Also, the main bore is counter-bored a little from each end so that the mandrel shaft only contacts it for about 9/16".
Dan Z.

Re: NOS Edison Standard mandrel bearing

Posted: Wed Sep 27, 2017 9:04 pm
by phonogfp
Dan, that's pretty slick having the original tag/part number with it. I've encountered a few of these over the years installed in Standards, but never seen a NOS example until now. I suspect the pot metal bearings developed problems early on, and Edison made these available as long as inventories lasted - even through the 1940s.

Thanks for posting it! :)

George P.

Re: NOS Edison Standard mandrel bearing

Posted: Thu Sep 28, 2017 9:20 am
by Jerry B.
Yes, very interesting. I wonder how soon, after leaving the factory, were there problems with the pot metal bushings? Do the purist among us prefer a reamed original bushing or an modern brass bushing or bearing?

How about Columbia cylinder machines with pot metal carriages. If you were considering the purchase of a machine would you rather have a repaired pot metal carriage or a carriage rebuilt from more stable metals?

Jerry Blais

Re: NOS Edison Standard mandrel bearing

Posted: Thu Sep 28, 2017 10:06 am
by phonogfp
Jerry B. wrote:Yes, very interesting. I wonder how soon, after leaving the factory, were there problems with the pot metal bushings? Do the purist among us prefer a reamed original bushing or an modern brass bushing or bearing?

How about Columbia cylinder machines with pot metal carriages. If you were considering the purchase of a machine would you rather have a repaired pot metal carriage or a carriage rebuilt from more stable metals?

Jerry Blais
As for Edison bearings, I'd just as soon install a new brass one so there's no future problem.

The Columbia carriages are a different matter. Very often we have no choice; if the carriage has swollen/crumbled and pieces are missing, a reproduction component may be the only option. I've seen some excellent reproductions, but also some marginal efforts. It's all in the execution. If the reproduction part isn't apparent, that's a win since there's no chance of future problem.

That said, there's an AG here that I've owned since 1983. When I acquired it, the carriage was frozen. After repairing it, it was nice and free for about 8 years. Then I noticed the half-nut (which rides up and down in two ½" deep holes) was sometimes hanging up. I disassembled the carriage and drilled out those two holes again - sort of a "root canal." Everything worked great for another 15 years or so - then it needed another "root canal." Just a quick clean-out...there was hardly any resistance on the drill bit. But the half-nut was nice and free again, and it has been ever since. I'm happy that the carriage is still 100% original, but should the time come that something needs replacing rather than repair, I'll be pleased to at least have the machine maintained in playing condition.

George P.

Re: NOS Edison Standard mandrel bearing

Posted: Thu Sep 28, 2017 1:15 pm
by JerryVan
"The main difference is that the center part of the outside has a rounded shape allowing it to roll around a bit if necessary to adjust to any misalignment."


Not the case at all. It's rounded because the pot metal has swollen and distorted it. I'll bet that the diameter is now way beyond anything that would fit in the bedplate.