Ceramic ball bearings too hard?

[haydn]

Has anyone besides Jaspert been following the discussion on Pink Fish Media  - http://www.pinkfishmedia.net/forum/showthread.php?t=77344 - about the ceramic ball used in the Kokomo bearing allegedly damaging Garrard 301/ 401 spindles?

If not, for those members that have a Garrard 301/401 turntable and using the Kokomo upgrade, it might pay to have a look at yours and see if your spindle is displaying the same type of damage as shown in their thread. Some of the Pink Fish forum members are claiming they are experiencing damage even after just playing a few lp's.

The issue revolves around the use of ceramic balls in the bearing which are harder than the spindle. Instead of sacrificing the ball, the bottom of the spindle is possibly being damaged at the point where the ball makes contact with it. So, are any Lenco Heaven forum members using a ceramic bearing instead of the original Lenco one?  If so, has anyone noticed similar type of damage to the Lenco spindle? I appreciate the Garrard bearing is a different type of bearing but if there are lessons to be learnt here, we should readily take them on board.

If we take on board at least one member of the Pink Fish's forum's insistence on only sticking to the original bearing type, then this leads to the question is any ball bearing material (other than the original) really satisfactory?

h

[daiwok]

I have read the thread. I have not notice anything with my Garrard bearing, but will take a look when I get it back. However, I am not overly concerned about it right now. I have been using a ceramic bearing on my Lenco for over 2 years now. No issues so far. The Ceramic ball bearing gives lower floor noise and better extensions to my ears.

I will report back if there is any difference. to be honest I cannot go back to the original bearing on the Garrard - sounds terrible.

[haydn]

David,
I know there are many users of the Kokomo bearing that are very satisfied with the resultant sound improvement and I wasn't wanting to be alarmist - I did say "allegedly"!

If a ceramic ball doesn't damage the Lenco spindle, I don't think we've anything to be worried about.

h

[daiwok]

David,
I know there are many users of the Kokomo bearing that are very satisfied with the resultant sound improvement and I wasn't wanting to be alarmist - I did say "allegedly"!

If a ceramic ball doesn't damage the Lenco spindle, I don't think we've anything to be worried about.

h

No problem Hayden

I am not defending the issue with the KOKOMO, I am sure the owner is looking it long and hard as there is a lot of bad post. The Garrard is not my main table  They should have designed the Garrard just like the Lenco spindle, I mean the EMT is similar to the Lenco spindle as well 

BTW - did you get your Mirko Bearing in the end ? I am still waiting for my replacement 

[d to the g]

This doesn't surprise me at all.  I've seen what little wear needs to occur for decohesion to occur.  If the wear is symmetric and smooth, then it's likely that the steel is soft and that the proper surface treatment has not been applied. 

My lenco bearing has been polished down by Jim Howard at applied fidelity just enough to allow for nitriding, which should allow me to run pretty much any ball/thrust/sleeve combination that I want.  It would take years of constant use to crack that nitride coating. 

Warning: I've done some consulting on thrustplate wear, and do mechanical testing for a living, therefore my views may be biased towards the use experiments and measurements. 

[daiwok]

This doesn't surprise me at all.  I've seen what little wear needs to occur for decohesion to occur.  If the wear is symmetric and smooth, then it's likely that the steel is soft and that the proper surface treatment has not been applied. 

My lenco bearing has been polished down by Jim Howard at applied fidelity just enough to allow for nitriding, which should allow me to run pretty much any ball/thrust/sleeve combination that I want.  It would take years of constant use to crack that nitride coating. 

Warning: I've done some consulting on thrustplate wear, and do mechanical testing for a living, therefore my views may be biased towards the use experiments and measurements. 

Doug,

Good point ! I might take my Garrard Spindle for some heat treatment and harden it up

[haydn]

BTW - did you get your Mirko Bearing in the end ? I am still waiting for my replacement  

Not yet but Mirko's sent photos of it and the modification is fantastic. I've discussed this with him and it just needs the side screw drilled and fitted and final polish then hopefully it'll be on it's way soon. This was part of the reason for looking at the PFM thread - my new bearing uses a tungsten carbide ball.  

[daiwok]

Not yet but Mirko's sent photos of it and the modification is fantastic. I've discussed this with him and it just needs the side screw drilled and fitted and and final polish then hopefully it'll be on it's way soon. This was part of the reason for looking at the PFM thread - my new bearing uses a tungsten carbide ball. 

Good stuff !! Hope you get it soon !! 

[rfgumby]

As the Lenco spindle bottom is cupped, the wear from a ceramic bearing would be on the thrust plate, which is easily replaced.  That's what it's designed to do right?

[richard]

What is the purpose of the plastic thrust plate?

Dual put a rubber expansion washer in approximately the same place. This is in the model 1019 hefty-platter record changer (and probably in other Duals, too). However, in Dual's case, there's a reason that's irrelevant in our situation, but I'll describe it anyway (since I regard these Duals as being "honorary Lencos that change records:).
The Dual, being a changer, has to use a hollow tube for the mechanism that operates the dropping spindle. So, the platter bearing design is like ours, but inside-out. The thrust bearing in these changers is a ball bearing race inside a steel cup. There's a tendency for friction to make the cup housing itself rotate; when it does, the mchine emits a scraping noise.

Tue rubber ring flattens out under the pressure of the heavy platter, pressing outward horizontally, stopping the cup from rotating.

It seems to me that any non-rigid thrust material would introduce at least some rumble. Why not (in the Lenco) steel instead?

[willbewill]

What is the purpose of the plastic thrust plate?

It is made of NYLATRON (Modified Nylon)

Main characteristics:

    * High mechanical strength, stiffness, hardness and toughness
    * Good fatigue resistance
    * High mechanical damping ability
    * Good sliding properties
    * Excellent wear resistance
    * Good electrical insulating properties
    * High resistance against high energy radiation (gamma and X-rays)
    * Good machinability

[Brumm]

Hi all,
I had a short look into the thread mentioned in the first posting, and think I have to add my 2cts also (maybe it's even worth less...)

First, I don't know what the bearing they talk about is, but in one of the answers Macor is mentioned. Macor is a machinable ceramic. In my model engineering circles it is used to make isolators for miniature spark plugs.
Further, in my new bearing i use a ball made of Zirconium oxide, and this stuff is d@#n hard! But it is also highly polished and truly round. But I hasten to add that my bearing had no opportunity to turn more than a few dozen turns. On the other hand, why should the spindle get damaged? Certainly the ball stays (almost) stationary in relation to the spindle, but turns on that tiny point on the thrustplate.

Nylatron is a nylon (PA6) with Molybdene disulfide added (Wikipedia is my friend). I almost wanted to ask the opinions about soft vs. hard thrust plates, but saw then it was already done somewhere (with no definitive result I think). Anyway, my plate at the moment is a piece of Lignum Vitae, but I am preparing another one from Tungstene Carbide ("Widia", if someone remembers the heated discussions with a certain Violette. AAS Forum iirc.). This one started as a triangular cutting insert. Top side now polished with the help of a couple of dirt cheap Chinese diamond lapping pastes.
Sorry, seems I am moving off topic now...
Greetings,

[rfgumby]

Hi Hansrudolph-

  Doug (D to the G) has a few lignum vitae thrust plates he's made, but I'm not sure if he's tried them yet.

You quoted:
"On the other hand, why should the spindle get damaged? Certainly the ball stays (almost) stationary in relation to the spindle, but turns on that tiny point on the thrustplate."

I agree 100%.   

I've been looking at some tungsten carbide pieces that I have laying around and I've been thinking that they would make a good thrust plate as well.  But I can't decide about the soft vs. hard debate...  I have ruby balls ready to try, but I can't decide which thrust plate they would work best with, so they're just poised and waiting.

[haydn]

Hi all,
Further, in my new bearing i use a ball made of Zirconium oxide, and this stuff is d@#n hard! But it is also highly polished and truly round. But I hasten to add that my bearing had no opportunity to turn more than a few dozen turns. On the other hand, why should the spindle get damaged? Certainly the ball stays (almost) stationary in relation to the spindle, but turns on that tiny point on the thrustplate.

In my very limited experience - and I will bow to the greater knowledge of forum members -  I agree with Hansrudolph, in that I have always thought the ball hardly moves at all. It's virtually a point-to-point contact with the thrust plate. Out of interest, has anyone ever tested this and can report their findings?

h

[d to the g]

In my very limited experience - and I will bow to the greater knowledge of forum members -  I agree with Hansrudolph, in that I have always thought the ball hardly moves at all. It's virtually a point-to-point contact with the thrust plate. Out of interest, has anyone ever tested this and can report their findings?

h

It's a rotating, and since it doesn't form a point contact there is both spinning and linear wear. 

I suggest everyone interested in bearing wear start by reading this: http://www.conradhoffman.com/Wear_pad_tests.xls