Vintage DD turntables. Are we living dangerously?

On the subject of platter mats I just want to re-iterate that I am using a lead mat glued to an Achromat. I thought that Fleib or someone else was about to try the same thing and wonder how that worked for them?

Lew,
"I hate to go into this yet again, but in theory one wants the tonearm and the tt bearing to be subject to the exact same external forces so they can respond in unison, resonate in the same way at the same frequency, etc, which should result in minimal dissociation between them in terms of energy dissipation."

That's where we disagree. As you pointed out, motor vibrations might be minimal in a high quality DD, but having arm and platter/bearing subject to the same external forces is a potential problem IMO. What about sound pressure waves hitting the record and plinth? The cart/arm already has to deal with this and might have to deal with it again if it's transmitted from plinth/chassis back to the arm.

I completely agree with Dover concerning BD or suspended tables, but if a DD is firmly planted where is the movement, the moving target? If a platter wobbles, it will wobble regardless.
The goal of controlled energy dissipation is to get rid of cart vibrations and isolate the arm from other ones. I think this is more easily accomplished w/o a plinth/chassis. The final exit of all vibrations should be out the feet otherwise it's just damped, although that might be sufficient.

In the real world either approach can be great or disappointing depending on design, materials etc.
Regards,

I wonder where is Halcro to argue the other side?

I think Fleib is doing quite a competent job....
It is clear from previous discussions that opponents of the free-standing armpod will never change their firmly held beliefs....so I felt no need to futilely inflame the situation...😡
I have never argued against the need for maintaining a perfectly regulated dimension from spindle to tonearm pivot....after all, it is the basis of all pivoted arm geometry.
The opponents of separate armpods appear to maintain that only a rigid horizontal member (the stronger and more rigid the better) is capable of achieving this requirement...?
This is a rather limiting view as gravity is a more powerful force than anything invented by man.
With a suitably massive armpod on spikes or appropriate footers, gravity and friction will ensure the necessary and stable relationship between spindle and tonearm pivot is maintained.
In the case of the Kenwood L-07D with its extended ribbed metal casting, it is easy to appreciate (and calculate) the dimensional expansion and contraction which inevitably extends and contracts the tonearm pivot point from the spindle centre with every one centigrade degree of temperature change.
This is NOT a recipe for dimensional stability...😱

The famed Continuum turntables have their tonearm mounting pads totally disassociated from the spindle and platter bearing, being suspended by wires from the top plate and held from the bottom with magnetism.

As Fleib has rightly repeated....it is execution rather than dogma which ultimately determines the value of the methodology.

Aigenga,
I won't bore you with excuses. I have yet to make the mat. Since the lead I have is about 2mm thick I'm thinking of getting the 3mm Achromat.

If anyone wants to experiment with sheet lead it's not hard to source online, but the shipping will usually be more than the product. I found some at a roofing supply. I think they call it flashing. This is a piece about 3 feet sq. and it cost something like $70.
Don't think this is used much anymore. When I called, the guy said they had no sheet lead until he remembered flashing. Wear gloves.
Regards,

regarding cantilevered armboards it seems to me we should look deeper into aspects like how long is the cantilever, which forces are put on, which are the mass ratios and which is the source of the resulting energy of the scanning process? If we do so we clearly see why the cantilever beam plays no important role!

Lewm, MS boards are flimsy??? When have you been standing last time on an original Micro Seiki armboard? Or do have double my weight? :-)

Fleib, Dover`s rules do apply to all TTs - regardless of drive mechanism.

Despite the convincing conclusion that platter and tonearm bearing should ideally not interact in relative movements I have experienced that it depends on the way of execution, e.g. in the Continuum or with my Toyo stand.

when the Victor arrives and has been repaired I will look into it again. Thanks all having supported me here so far and exchanged ideas - very helpful indeed !!!