New acrylic platter for the SL-1200/1210

[DSJR]

Indeed not. A simple test of spinning the platter with the power off shows that it is a very well engineered bearing with small frictional losses.

In my ignorant world, friction is one thing, drag is another (try charging a stock bearing with hypoid viscous gear oil and feel the difference. i call this "drag," for want of another term).

Apologies for upsetting experienced engineers..

[MartinT]

Umm, if there is low friction and the platter spins for a long time, there cannot be drag. The oil that Mike supplies is nothing like as viscous as hypoid.

[WOStantonCS100]

In my ignorant world, friction is one thing, drag is another (try charging a stock bearing with hypoid viscous gear oil and feel the difference. i call this "drag," for want of another term).

Apologies for upsetting experienced engineers..

My apologies, Dave, if I exacerbated things. It was just that your post wasn't at all specific or clear. Left alone "drag", concerning a bearing, is a pretty negative connotation; so, I can understand Mike's alarm as it did cause me a bit of alarm as well. Even so with your explanation, and mind you neither am I a bearing engineer; I would imagine, if I were, my first quality control check would be to see how the bearing performs under minimal load. If it "dragged" then, there would be no testing with a heavier load. It would immediately be back on the bench for a "re-drawing". I understand what you are saying about "viscosity"; however, it was my understanding that the MN bearing was meant to work with the original platter, as well as, the MN platter, so careful consideration would have to have been given to the matter at the time of design. Mike speaks well for himself, so I'll leave it at that. Again, I didn't mean to rumple feathers if I did.

[Mike_New]

DSJR,
I can only say in my defence that the term "drag" as defined by Collin's Dictionary
means 'to pull draw or move with some effort'; 'to move or pass with effort"
"to force into action"
I just feel it is not the term one would use to describe it's performance. as Biff observed.

[Marco]

Anyway, I'd have thought Dave would've known all about "drag", being a 'queen' at the weekends, eh dahhling?



Marco.

[WOStantonCS100]

Anyway, I'd have thought Dave would've known all about "drag", being a 'queen' at the weekends, eh dahhling?



Marco.

Are we talking about bearings or Chaz Bono... or is it Chastity Bono... or is it... I digress, my bad... back on track.

[YNWaN]

http://www.skf.com/portal/skf/home/p...ewlink=1_0_38a

[Mike_New]

Unfortunately not the same thing, it refers to drags losses of a bearing partially or totally submerged in lubricant (oil). What happens is that as the bearing rotates there is indeed a drag as the balls rotate through the oil.
My bearing is a plain bearing which is a bit different.

[DSJR]

Anyway, I'd have thought Dave would've known all about "drag", being a 'queen' at the weekends, eh dahhling?



Marco.

Yeah, HiFi Dave and I have a lot to answer for

[YNWaN]

Unfortunately not the same thing, it refers to drags losses of a bearing partially or totally submerged in lubricant (oil). What happens is that as the bearing rotates there is indeed a drag as the balls rotate through the oil.
My bearing is a plain bearing which is a bit different.

Indeed, I linked to this item purely because it discusses bearing drag as a concept, independent to friction. However, the shaft of most plain bearings is entirely submerged in lubricant (as discussed in the linked article) and shear forces will exist within the oil film interposed between surfaces (this is true of any lubricated surface and is not intended as a criticism).