SME 3009 II - pillar barings change

by **dominic harper** » 07 Nov 2010 21:01

Hi Rene,
use some wire wool to clean the bearing shaft and replace the bearing races.Make sure the shaft is spotless before re-assembly.
Be sure to wash the new bearings in alcohol or even contact cleaner to remove any oil. The bearings should NOT be oiled for use. Re-assemble and rotate lower bearing cap until minimum amount of play but free running bearings.
Regards, dom

by **classicus** » 08 Nov 2010 12:13

Hi,
This the state of the bearings

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and the pivot...

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I have tried using

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a cleaning product for vinyls electronics... de-greasing and anti oxyde...
first results are not too bad.
I probably will be able to get it back functional..

However I followed the new bearings path and found a specialized supplier with exactly what we are looking for...
$\:D/$ $\:D/$

http://www.bocabearings.com/search.aspx?SearchType=StartDimension&radix=metric&Inner=9.0000&Outer=17.0000&Width=4.0000&InnerOperator=%3d&OuterOperator=%3d&WidthOperator=%3d

at $11 it seems to beperfect, or even $13 for full stainless steel, I cannot see any advantage going to ceramic, for the use these bearings will have...

Thanks again for the good tips
René
the most expensive full ceramic bearing at $90 :shock:

I have noted that they need to be broken in, I would thave to make a little device for that...

by **classicus** » 10 Nov 2010 14:25

To supplement my previous post, I made a diagram of the pillar construction

I have enquired about Boca bearings, Boca proposed a dry lube treatment.

I think it may be the right thing to do as it certainly is not recommended to have oil or grease which would probably dampen their movments.

I understood also that they recommend running them in before obtaining normal performance

by **classicus** » 10 Nov 2010 20:23

to be exhaustive
The same drawing inclusive of the bottom cup locking screw

by **classicus** » 11 Nov 2010 12:11

As regards the bottom cup being attached to the shaft, with difficulties to take apart, since the little allen screw does not come loose :roll:

.

NEED for help :?:

1- from what I can see, the shaft is screwed into the bottom cup (the same way the the shaft is screwed into top yoke) and the little screw I cannot undo is probably diving in the shaft screw fillet to block it...
2 - The allen recess had probably been damaged :evil:

... which adds to the difficulty

Can anybody confirm this design, and give an idea (beyond soaking it for some extended time in kerosene or ...) to loosen it? :?:

by **classicus** » 12 Nov 2010 18:43

2 updated diagrams (to replace the previous ones)

by **donic** » 20 Nov 2010 19:30

classicus wrote:Hi,

However I followed the new bearings path and found a specialized supplier with exactly what we are looking for...
$\:D/$ $\:D/$

http://www.bocabearings.com/search.aspx?SearchType=StartDimension&radix=metric&Inner=9.0000&Outer=17.0000&Width=4.0000&InnerOperator=%3d&OuterOperator=%3d&WidthOperator=%3d

at $11 it seems to beperfect, or even $13 for full stainless steel, I cannot see any advantage going to ceramic, for the use these bearings will have...

the most expensive full ceramic bearing at $90

And what about a possibility to use closed ball bearing which are lubricated at a factory and after this closed? Can be used for SME or only open ball bearings without any lubricate are okey for tonearms?

for example this kind of bearings

http://www.bocabearings.com/bearing-inv ... AF2-9x17x4

regards, donic

by **donic** » 20 Nov 2010 20:49

Hi,

One more question, is it better to buy SMR689#5 instead of "normal" SMR689?

http://www.bocabearings.com/bearing-inv ... 895-9x17x4

The first one is ABEC-5 and the second one is ABEC-1?

Is it important ?

regards, donic

by **classicus** » 29 Nov 2010 11:07

Hi,
Just updating my previous drawings since I was able to completely undo it my tonearm pillar (confirming bottom cup assembly).

unfortunately, it is not possible to edit previous posts ro replace former drawings.

In a tentative answer to Donic questions, I have no knowledge of the effective difference between different bearings in a tonearm, I am just trying to replace faulty ones (no way I can clean the original ones completely).

The stress put on the ball bearings in a tonearm, extremely slow and regular micro movment across a 70° max angle, is completely different from what they are made for; these bearings are designed to spin at relatively very high speeds.

I've just received from BOCA Bearings 2 SMR689 #5 Radial Bearings 9 x 17 x 4 Millimeters treated with UDL lube.
BOCA has been very responsive and cooperative... and very quick shipping... =D>

I ordered those on the following reasonning:
- ABEC 5 (#5) should correspond to better precision and efficiency,
- UDL treatment, to avoid any oiling,
- open since the original ones are open and the pillar assembly itself makes an enclosure.

It seems clear that I will need to run them in. I'll do that on a makeshift (electric drill) device runing them hight spped for few hours turning both ways.
When my tone arm will be in operation again, I will report...
Regards
René

by **donic** » 29 Nov 2010 16:21

classicus wrote:Hi,

I've just received from BOCA Bearings 2 SMR689 #5 Radial Bearings 9 x 17 x 4 Millimeters treated with UDL lube.

Regards
René

Hi Rene

Are these bearings specially made on your request/order ? I'm asking as looking at technical data of SMR689 #5 there is nothing about this special kind of lube. Boca writes they use Shell AF2 Oil not UDL lube.

http://www.bocabearings.com/productDeta ... temID=2624

I was also thinking about Boca but becuase their bearings are made in China I was a little bit sceptical about quality of their products. Maybe I shouldn't think so?.

Finally I decided to go for made in Japan EZO bearings, which have good reputation in small precise bearings business. Unfortunatly EZO are ABEC-1 instead of Boca's ABEC-5.

Regards, donic

by **Mark Kelly** » 30 Nov 2010 09:12

Some additional information for your drawing above:

The thread where the top of the pillar screws into the yoke is 1/4" British Standard Fine (26 TPI).

The thread where the bottom of the pillar screws into the adjusting collar (the part you have labelled as "bottom cup") is 8 mm metric extra fine (0.75mm thread pitch), the grub screws are M3.5 (0.6mm thread pitch, the M designation means metric standard coarse)

The "pillar thread" where the pillar is joined to the base is 23mm metric ?fine? (1mm thread pitch). The question marks are because this is not usually listed in the metric fine threads and is uncommon except on bicycles where some crank dust caps use this thread.

by **classicus** » 04 Dec 2010 14:02

Donic:

My amateur device for running in the bearings:

After making sure that the bearing axis is right, I make it spin holding it gently (avoiding any stress), over a minute each way at increased speeds..

After having done the first one, I have the feeling that there is a difference between the two. more suppleness, and I have the impression of a much longer spinning time...

So I think it's a good trick... My few minutes of spinning is probably more stress than what they would receive in 10 years as tonearm bearings (at least they would have made some full revolutions)....

I just needs to assemble the whole arm + finish my Lenco GL88 plinth + get the whole set up to work... to listen to it...

Mark, =D>

Great information, I'll add it to my drawing next week.
René