Acrylic platter

Lewm.

No I am not that brave/reckless. I have the original platter complete. I took measurements from this and machined up a new magnetic housing.

Re acrylic, I think that the trick is to get to the higher transmission speed material thru a minimum amount of acrylic. You could say that I am using a duralium platter with a bonded acrylic mat. The acrylic part of the platter is only 6mm thick.

thanks

Lewm.

I may have misunderstood your question....
Yes, I changed the motor magnet and speed sensor cup over from the original platter into a newly machined dural housing.

Dear Lew, Exactly what I thought about Richard: 'fearless and adventuresome'. Who else would dare to mess with, uh, 'the best' DD TT ever? In my previous post I mentioned to have 'some idea' how metal platters are 'balanced'. Well by my first Thorens I noticed those 'holes at random' on the underside of the platter. Those were the balancing 'holes'. By my next TT, the Linn LP-12 there were no such 'holes' so the only way to balance this platter is on the (CNC?) lathe. I also owned 3 different Linn platters and all of them have had different weight which means that they were 'processed' on the lathe till they were balanced. To my mind and in retrospection the only part of this TT which is made well and probably the explanation of its succes. As you I also have 'my own machinist' who owns an CNC lathe. Observing this kind of work is like looking at some artist. Those 'machines' move on way or the other but always around. To be able to make whatever on those machines is like an wonder. This imply mastership in order to produce an masterpiece. And those well balanced platters are each an masterpiece. BTW both platters on my previous Audomeca J1 and Kuzma are 8 kgr. each and both with inverted bearing. So I suspect that if the use of lead was allowed Kuzma would copy also this material from Lurne(grin). If I was not 100% sure that he is from Slovenia I would think that he is Chinese...Besides I never told to anyone in Serbia that I bought whatever from Slovenia...

Dear Nandric, I have no feel for the politics of Eastern Europe, now that the war is over (thankfully), and all the countries involved have new names and different borders. I don't really know who hates whom these days.

The Lenco L75 platters were also dynamically balanced, and each one will have small drilled impressions on its inner aspect, indicating where mass had to be reduced to bring that particular platter into balance.

I don't know if the Mk3 is "the best". It is surely terrific, but I would like to have a shoot-out among three or four of the top contenders, done under well-controlled conditions. (Same tonearm and cartridge, same system, same listeners, but more than one.) Someone might reference the shoot-out that was published in a Japanese magazine in the 80s, but that one was not well controlled and did not include the Mk3 at all.

Nandric.

I agree, there is an art in operating the CNC machines.
In our CAD/CAM shop, different operators produce different "quality" even though they are using the same program. Figure that.
I have dynamically balanced my composite platter by removing a few grams.
The MK3 is good, but the motor and that of its little brother, the MK2, can be made much better :-).
There are many contenders for the "best" and in the end it largely depends upon personal preference. One man's poison and all that.