VPI Super Platter

I looked at the bottom of my MK III bearing and the ball looks pressed into the metal. No periphery ring holding it in and no way (that I can see) of prying it out without damaging something. Is there a trick to getting it out?

Also, the original steel ball looks smaller than the 1/4" Silicon Nitrides that I ordered. I doubt that they are the same size. Or is the MK III just a very different animal from the above?

Bob

Pull the steel ball bearing out with a strong magnet.

Hello Bob/All,
Perhaps use a little Lighter Fluid (Naptha), or some other suitable Solvent (Paint thinner) on a piece of Kleenex to cut-thin, and clean the caked up Oil that is retaining-holding the Ball to the bottom of the Shaft.

It will be intersting to see what your findings are, and if you have a Dial Caliper, I'd like hearing what measurements you come up with on the original metal Ball? (And what the actual diameter is too of the Ceramic Balls?)

I've yet to operate on my MK-IV Bearing as of yet, but will try to get around to it soon, and see what numbers I come up with?

I am not totally sure about this as of yet, but from talking with some knowledgeable people just recently about these Bearings, and thier design principals, I am beginning to believe that the Metal Ball itself was really not intended to be rolling-rotating within the retaining Cup of the Shaft itself, but rather to stay stationary, and to only be rotating at the very small contact area which is in contact with the bottom Bearing Trust Plate.

I'll try researching this some more, but evidence in some of the AA archives seems to point to the fact that some have noted flat spots on thier Bearing Balls, and probably one cause of this, was perhaps neglect of periodic Lubrication?

I would assume that at some point in time, due to extreme PSI weight at this Bearing-Thrust Plate interface, it is inevitable that wear will begin to occur.

Whether the Ceramic Ball will be a considerable improvement in operation, and performance, it's hard for me to say at this point, as Ceramic does appear have some better qualities versus a regular Metal Bearing Ball (Smoothness-Hardness-Roundness) but also possesses some qualities such as high heat resistance, and corrosive resistance which may not be so important in this specific application?

Questions that arise in my mind, are, without anything else in this Scheme being changed (Thrust Plate staying the same) will there be a worthy benefit?

Since the Bearing Shaft only requires one Bearing Ball, it is not at all cost prohibitive to perhaps try, and see? Now if I needed a 100 of them, that would be a different story altogether! ;-)

One day perhaps soon, I suppose it couldn't hurt getting on the horn with Mike@VPI, and pick his brain on this topic?

Since the Platter, and Bearing removal is a 3 minute affair, I may delve into this soon, and report back on my findings with some measurements of my own to add.
Mark

Thanks guys. Now to locate someone with a "very strong magnet". The only ones I have around here are holding pictures and report cards to the 'fridge - and they fall off all the time.

I'll try thinning out the oil/grease under the ball also. I'm sure part of what's holding it is suction in the cup. I truly hope it's not "pressed" into the metal.

Yes, the ball does rotate, but not freely as you might expect. I would definititely say it is designed to rotate about the one contact point and not spin all over the place. So lubrication, and plenty of it is definitely the name of the game. It probably should float in oil and not have just slick grease around the chamber.

Enjoy,
Bob

Contact VPI. Harry has a new lubricant. It looks like petroleum jelly, but he assures me its not. It did make positive changes in my Superscoutmaster