Spindle Bushes

301, 401, plinths and assorted idler stuff
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Paul Barker
Oooo, Roberts Radio's sound nice
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#1 Spindle Bushes

Post by Paul Barker »

My 301 has steel bushes in it, surely Garrard didn't use steel? Is there any harm in this? Should I get them rebushed with bronze?
Clive
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#2

Post by Clive »

I have the same Paul, I plan to send my bearing to Darren soon to re-juvenate it. Whoever came up with the steel bearing needs shooting.
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Greg
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#3

Post by Greg »

If these steel bushes are as common as Darren and owners are finding, I'm wondering if Garrard themselves fitted them for a while, maybe at the transition from grease to oil. I just find it hard to believe that so many bearings have been subject to resleaving.
Darren
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#4

Post by Darren »

Sorry Greg,
I'm afraid I don't believe that's the case. I have found these steel bushes across a wide era of Garrard turntables on models from 301s to 401s.

Add the fact that they are very badly made I don't think they could possibly be Garrards doing.

More like some re-furbisher has been very busy indeed fitting these for some time. In my honest opinion these steel bearings need to come out and be replaced asap. For a start steel is the wrong material in this application causing damage to the platter spindle. Secondly it has been noted that steel bearings do nothing for the sound and bronze gives better results.

More information can be found here http://www.slatedeck.com/turntables/Gar ... rings.html

best wishes
Darren
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adhoc
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#5

Post by adhoc »

Darren,

If steel bearing bushes are able to wear out the hardened steel spindles, wouldn't a ceramic bearing ball wear a concave spot into the end of the spindle?

And any ETA on the replacement bushes? Will this be a user-replaceable modification or a job done by you good folks?

Cheers,
Aaron
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adhoc
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#6

Post by adhoc »

Something just crossed by mind.

Assuming the ball bearing will eventually wear a pit into the bottom of the spindle, why not have the ball bearings free to rotate within the bottom of its holder as well?

This way the "wear" is "split" 2 ways - 1/2 goes to the spindle tip, while the other 1/2 goes to the holder. A concave cup-like holder would do perfectly, no?
~ Aaron
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Nick
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#7

Post by Nick »

What you have described sounds very much like a lenco bearing.
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adhoc
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#8

Post by adhoc »

Nick wrote:What you have described sounds very much like a lenco bearing.
Dang. Reinventing the wheel huh? :oops:

I had no idea, I have never owned a Lenco before. Only a Thorens and a Linn.

Still though, does the idea hold any promise?
~ Aaron
Darren
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#9

Post by Darren »

adhoc wrote:Darren,

If steel bearing bushes are able to wear out the hardened steel spindles, wouldn't a ceramic bearing ball wear a concave spot into the end of the spindle?

And any ETA on the replacement bushes? Will this be a user-replaceable modification or a job done by you good folks?

Cheers,
Aaron
Hi Aaron,
Welcome to the forum..

We need to considerer the properties between the two materials of steel and ceramic. Steel has quite a coarse grain structure and as such can be quite an abrasive material. Though if manufactured properly is quite suitable as a bearing material in the right application. Ceramic on the other hand is quite the opposite having an extreamly fine structure that can be polished to an astonishingly high standard. Ceramic is already widely used in industrial bearing applications and has proved itself to be a superior product.

Having said that, the replacement steel bearings I have come across in Garrard turntables are made from a common garden and very cheap quality material and to add to that they are also very poorly machined.
In each and every case I have personally come across the spindle shafts have shown some signs of early damage. One or two I have scrapped making the rest of the turntable only suitable for spares. Hardened spindle shafts would simply cost too much to have made new. Fortunately in most cases we can simply "move" the position of the bearings in the housing to avoid the damaged areas.

It's has surprised me just how many Garrards units have these replacement steel bearings. About half of all the turntables I have had pass my way. The clearances are quite good and when first fitted I have no doubts the owner was overjoyed at the improvement in sound. But I'm afraid this new gain would probably be short lived as the bearing starts to dig into the shaft. No doubt a slow process that would go easily unnoticed until it becomes too late to salvage the shaft.

Slatedecks replacement bearing are now available but we are currently out of stock of ceramic balls for the thrust bearing. Not really an issue as we can order some in next week.

This page may be of further help Aaron http://www.slatedeck.com/turntables/Ser ... rices.html

Best wishes
Darren
Darren
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#10

Post by Darren »

adhoc wrote:Something just crossed by mind.

Assuming the ball bearing will eventually wear a pit into the bottom of the spindle, why not have the ball bearings free to rotate within the bottom of its holder as well?

This way the "wear" is "split" 2 ways - 1/2 goes to the spindle tip, while the other 1/2 goes to the holder. A concave cup-like holder would do perfectly, no?
Hi Aaron,

We thought long and hard about this one when designing the lower thrust bearing and did indeed try ally, stainless and brass lower cups to house the ball bearing. In these the ball sat freely as you suggest.

One of the biggest enemies for turntables is vibration as no doubt you are aware. When two objects move against each other friction comes into play and thus causing vibration. So we considered this and tried fixing the ball bearing to the carrier in an attempt to remove one possible source of vibration. The improvement was subtle but it could be heard, or not, as the case may be.

Later we tried a composite material as opposed to metal in our experiments. This gave a bigger change than "fixing" the ball in the carrier. Our conclusion to this was that either the composite housing was offering some spindle isolation from the rest of the turntable. Or it was damping the vibration of the spindle/ball relationship. Not a bad thing I think you'll agree.

The idea looks simple, and indeed it is. Though it did take about eight months to finalise the experiments and come to these conclusions. Rather a lot of work for such a simple little part !!!

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D.prese

#11 Spindle Bushes

Post by D.prese »

G when you say warm up -it is one time in a day right - say if the spindle does not operate for 1 hr - will it need to be warmed up again?

RGDS
Irfan
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