Help needed: Rega P2 knocking

[Countryman]

I purchased my P2 in 2020. It ran silently until about 10 days ago.
My taking it apart, and adding a tiny amount of lubricant seems to have worked - at least for the mean time.
I may investigate further.

 

[Craig B]

I purchased my P2 in 2020. It ran silently until about 10 days ago.
My taking it apart, and adding a tiny amount of lubricant seems to have worked - at least for the mean time.
I may investigate further.

For the benefit of others:

Had you ever removed the hub/spindle from the bearing well before?​

An equally important question:

Did you originally pick the turntable up from a dealer, or was it shipped to you?​

 

[Hazelberry]

Current P2 was introduced in May 2016. As the OP describes his as 'the latest P2' he may not have been using it for long.

As reference, I've a hub/spindle here that had obviously been run dry for a very long time. This from an otherwise minty Planar 3/R200, so April 76 through just prior to April 83 vintage. The original owner pulled the hub out to show me its condition, and it was dry as a bone with a dimple that was hard to miss. Under a magnifying lens the ball looked for all the world like a classic black and white soccer ball. Funny enough, a thorough clean and lube and this deck actually sounded quite good as was. The spindle shaft was surprisingly unmarked and shiny. Regardless, I replaced hub/spindle and ball soon after.

Planar 3/R200 vintage run dry bearing pictured below. Another couple of decades of such abuse and this would have been fully converted to captive ball. Spindle side beautifully burnished to a perfect mirror finish, likely more perfect than when new.

P3 2000 bearing below. Some spindle end forced down marks from bloke who just couldn't resist pulling his out to impress guests. White specs are micro dust particles, as I neglected to give this one a final flick of the duster prior to the shot.

And, here are the balls that came with each. After a good clean I couldn't tell which came with what without using my jewelers loupe. The one one the left isn't actually dull, just not given a polish before taking the photo (could be the one from P3 2000 with dust on above).

What's that fluting on the spindles, Craig? I've not seen it before.

I've mentioned it before but I had a worse dimple on the end my own original subplatter spindle. It resembled a golf ball dimple! The deck had seen heavy use by myself & the bearing must've been dry for years. As per your examples, the ball itself was fine. The TT sounded better after I cleaned everything & lubed the bearing but a new subplatter made a giant improvement.

OTOH a very old subplatter made of a more flexible plastic, also in a dry bearing, that came with a c. 1980 P3 plinth had a dimple on the spindle only a little bigger than your second example.

 

[Craig B]

What's that fluting on the spindles, Craig? I've not seen it before.

I've mentioned it before but I had a worse dimple on the end my own original subplatter spindle. It resembled a golf ball dimple! The deck had seen heavy use by myself & the bearing must've been dry for years. As per your examples, the ball itself was fine. The TT sounded better after I cleaned everything & lubed the bearing but a new subplatter made a giant improvement.

OTOH a very old subplatter made of a more flexible plastic, also in a dry bearing, that came with a c. 1980 P3 plinth had a dimple on the spindle only a little bigger than your second example.

The apparent fluting on the spindles are reflections of the radial strengthening ribs round the bottoms of the hubs.

I suspect that the size of any spindle end dimple will largely depend upon whether or not lube has been lost combined with how often the turntable gets used. My second photo above is of a P3 2000 spindle end and is typical of what I've seen on many Planar over the decades.

Something to keep in mind here is that with none captive ball bearings the spindle rotates upon a self-aligning stationary ball, whereas a captive ball rotates upon the bottom surface of the bearing well. If one is going to be making a hardened steel spindle anyway, there is really no need for a hardened steel thrust plate below, nor any uber accurately centre drilled recess (captive ball), nor any ultra accurately tapered/radiused spindle end, when flat parallel surfaces will have an accurately round hardened steel ball automatically centering itself.

 

[sq225917]

There's no way to know if a none captive ball spins on both surfaces or not, all the time, or at different times. One can only guess and assume via degradation of both surfaces.

The smart engineering move, would be a fixed ball with softer pad necessitating replacement of only one part. Garrard style.

Or, a loose ball if the cost of replacing all the parts is less than the engineering cost and parts of replacing just one as above.

Knowing rega I'd suggest they chose the 2nd route for those reasons.

 

[Craig B]

There's no way to know if a none captive ball spins on both surfaces or not, all the time, or at different times. One can only guess and assume via degradation of both surfaces.

The smart engineering move, would be a fixed ball with softer pad necessitating replacement of only one part. Garrard style.

Or, a loose ball if the cost of replacing all the parts is less than the engineering cost and parts of replacing just one as above.

Knowing rega I'd suggest they chose the 2nd route for those reasons.

With a none captive single ball bearing between two flat surfaces, as the spindle is being driven by the hub, any resistance due to friction will be broken between spindle end and ball before ball and brass floor below (i.e. there isn't enough friction to hold the ball captive until such time as it is captive, IYSWIM). The opposite would be true if a given spindle remains stationary whilst a flat bottomed sleeve rotates opposite a ball, as in inverted turntable bearings (although these balls are usually captive for ease of assembly).

 

[sq225917]

I'm.curious how does the ball know which surface is rotating? Surely whichever is the smoother, harder bearing surface will lose grip?

 

[Craig B]

If we are going to anthropomorphize Rega turntable bearing parts, then it is my contention that it is the spindle that (whom?) doesn't 'know' what's going on the other side of the ball, it just 'knows' that it can't hold onto the slippery thing and spin round at the same time.

A dry bearing will be a different case altogether, as this will be likely to precess which will shift the ball once every revolution, with the knocking being the ball getting back home into the dimple again whilst under the weight of the glass platter (i.e. not audible when the platter is off).

 

[sq225917]

Are rega bearings flat bottomed internally, I thought they were concave, pretty sure my p5 was. I guess we'll only know when someone makes a sapphire sleeved unit.

 

[Craig B]

Are rega bearings flat bottomed internally, I thought they were concave, pretty sure my p5 was. I guess we'll only know when someone makes a sapphire sleeved unit.

P5 shared the old style standard Rega flat bottom brass bearing well with the lesser models, whereas, P7 had the P9 bearing, which was the basis for the RP10/P10 tapered/radius tipped spindle running on a flat thrust pad that is set into the brass bearing well. I say 'basis for' as P7/P9 bearing had a removable bottom plate secured with 3 x machine screws, whereas, the RP10/P10 bearing is solid brass all round.

Rega RP10/P10 bearing:

Current 'self-tapping' P3 bearing well:

 

[sq225917]

Ooh, good cutaway.

 

[Craig B]

Ooh, good cutaway.

Yes, they did a nice job on that.

No doubt, given a couple of drops of 80-90wt Hypoid gear oil Rega's cutaway bearing will still outperform anything that Technics has ever made, and likely for longer than Technics between re-oiling too.

 

[sq225917]

The structure is a bit iffy on the technics and the thrust pad set up ain't brilliant but the oilite bearing bit is good

 

[Craig B]

Here is the reason why the Technics is open on one side at the bottom.