Vintage Denon Direct Drive Turntable

Hi T_bone
I spent some time scratching my chin on this one. I was toying with the idea of having a corner piece cut out of the plinth, rounded off and bore it for the arm, whereby it would 'sit' inside the concave rounded corner without actually touching the plinth, much like the Michell Tenodec, this would allow the arm to be moved idependently of the plinth to accomodate different arms. But it would be very costly, so in the end I have decided to commit to one arm (10.5" S-shape Jelco) and have a hole drilled out in the one-pice plinth, so no going back now!

Treehugga, I've done the same thing in my Denon slate plinth, which is not quite so massive as yours (50mm thick vs 100mm). I use a Triplanar, so all that's required is to locate and drill the three bolt holes for its base. It's easy to drill slate with a masonry bit as long as the hole is relatively small in diameter. I have identified several very fine tonearms that can be surface-mounted, like the TP. These include the RS-A1 (which needs no drilling at all), the Terminator 2, and the Dynavector 505. I'm sure there are more that I don't know about. I reckon my plinth weighs 60-70 lbs AFTER cutting out the hole for the Denon, so yours is a true monster in terms of mass. Stay tuned.

Lewm
How did you get on with the tricky holes on the edge of the motor unit cut-out? I can't find m4 bolts / machine scews longer than 60mm, so unless I bore slightly larger holes from underneath to a dept of 50mm in rder fasten a nut on each bolt, i'm stuck. That's why I'm going for threaded inserts. Thanks for the heads-up re: surface mount arms, I had no idea such arms existed. Isn't the Terminator a linear tracker arm? there is a guy over here using one of them with an SP10 on a slate plinth, it looks totally brutal.

Thanks Treehugga. If you wanted to have slate cut out at half height partway into the block, does that work? Or does it have to be the same vertical cut through the piece? In a simple example, I am thinking of a cylindrical cut out with diameter of 6 inches going halfway through the block, stopping there with a horizontal plane, and then having a further cutout of 4 inches' diameter going the rest of the way through. If so, that makes for some interesting possibilities, but I do not know how these things are cut. Perhaps the only way to do that is to cut two pieces with super flat surfaces (with cutouts beforehand) and bond them.

Treehugga and T_bone, As I now understand the operation of a waterjet, it cannot make router-like cuts and patterns; it can only cut the material all the way thru. This obviously imposes some limitations for plinth designs. I would have liked to have been able to create a recess into which one could insert a tonearm mounting platform. T_bone, I am not sure I understand your idea, but I think it cannot be executed with a waterjet. You'd be able to do it with separate layers of slate. Treehugga, at my suggestion, the CAD guy designed the program so that the three holes for mounting the Denon were cut FIRST, before the major central cut-out was done. This worked out fine.