Wednesday, June 20, 2018

Finding My Bearings.....

Rotary "Swivel Rocker" bearings, to be precise, something quite similar to a Lazy Susan bearing, but with springs, like this:


Instead of the bottom bearing plate bolting directly to the structure, it's suspended by springs to a third plate which bolts to the structure.

The one being replaced doesn't look nearly as good:



It was raining steel bearing balls when the guy she bought it from brought it into the den (hey, twenty dollars delivered!), so I grabbed one and measured it to be .375". OK, close to the size that's used in my Yaesu antenna rotators, and it looks like a standard inch-size, so off to the web, where I got 100 .375" stainless steel balls for six bucks, free shipping.

Now having used these before in various projects, I've always put enough balls in the races to fill them to 85%~90% capacity, leaving enough space for a generous dollop or two of grease. And silly me, I assumed a mass-merchandised-built-to-low-cost piece of  furniture would use components that were more to a spec I'm used to.

Nope, it used 8 balls caged in a little nylon ring, and a minimal amount of grease or oil.



I also learned that this is a "Three Spring" assembly, so it has a different feel than if it had two springs and a solid stop. Previous to learning this, I'd wondered where this piece of a broken spring had come from. You can clearly see where the coil broke on the upper end. I've seen valve springs do this, and it usually attributed to either exceeding the design limits of the spring, or faulty metallurgy. Once I found the spring, and saw the pictures of new units, the failure mechanism became clear. The spring failed, causing the bearing assembly to be subjected to bending moments far greater than it was designed for. The races spread apart, a ball popped out of the nylon cage, got jammed in there, and then jumped out of between the races, and it snowballed from there until the guy put the chair on some local list my wife gets.



Anyway, it's not economically viable to repair this. The "axle" through the center is peened over on one end like a large rivet, and that stops me right there. I'd have to thread the shaft and use a nut, and that aint gonna happen. The first new one I found was $97, plus undisclosed shipping, but some more searching found the same thing for $47, plus $7 shipping. Now that I know what they're called, I can search deeper.


Worth $75 total to fix this thing up?


She thinks so, and I don't mind doing it, as long as I can get the parts. I think they're neat chairs, and this one also came with a matching footstool. They're fairly comfy if the padding is good, and the little ones will love that it swivels and rocks. I might have to do something about a potential Pinch Point where the two sections go together and little fingers could go there, too.

Nope, still not my Eames Lounge Chair and Ottoman, but you have to start small, and besides, we saved this from the landfill.


13 comments:

  1. It's always something ... sigh. But the project seems worthwhile, if it can be done economically. And the price you quoted is WAY cheaper than buying it new.

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    1. Not a real big deal, Rev. I've used "Lazy Susan" bearing assemblies before for making stuff, but never had to replace one to fix something.

      The springs in it surprised me when I took the base off. Never though about one that spins AND rocks before....

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  2. The cost of the repair is part of the equation, other parts of the calculation may include whether I get a new tool out of the job, will the repair involve welding or machine tools, and sometimes, will the repair involve (frankly) being able to show off my repair skills.
    And I skipped past the most obvious part of the equation. Will this make my wife happy!

    Changing the swiveling spring base to something that involves reusing some constant velocity joints, and an air shock suspension would be, interesting.


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    1. Only if I can figure out how to inexpensively motorize it, John!

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    2. And WSF is 100% correct....

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  3. Well, it's good to know that somebody, somewhere, still tries to repair things instead of just throwing them away and buying something new.

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    1. I absolutely, positively HATE throwing away something serviceable. If I can get the parts to fix it, I'll at least try.

      One of these things new would be over $200 with the footstool. The new rocker bearing was $55 shipped. A couple of pieces of the bamboo have come loose, but from looking at how the chair id made, all I have to do is clean some dirt off the bamboo, glue it and clamp it, and you'll never know it had separated.

      For $75 and a few hours of my admittedly cheap labor, we'll have a nice "Retro 60's" rotating, rocking, comfy chair.

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  4. I would check out your local craigslist for sale or free sections for a similar chair. Sometimes, you can buy a similar item for parts for less than the parts themselves. Similar to buying a parts car. Any project is just an excuse to buy another tool.

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    1. I'd have to go and personally inspect each chair and scratch those with shot bearings. And considering when and how this assembly was made, I suspect it's the first thing to go.

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  5. I have to agree with WSF and well done!

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    1. Thanks, Parson. I hate chucking fixable stuff in the landfill. My Dad always said to "Use It Up, Wear It Out, Make It Do, Or Do Without", and I guess the lesson stuck.

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  6. Ah, basket chairs... Cheep is the word for their mechanicals... Finest pot metal in the Philippines! :-D

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Keep it civil, please....