Thor, or should that be Zeus?

[Chaz]

Think I'd be more inclined to have sleeve machined for the Spindle then set this in concrete. Don't think you'll get the strength/accuracy required from casting alone and will be bitch to remove spindle.

With the DWH epoxy, it will follow the shape down to the micron. That is one of the uses of the epoxy and it doesnt shrink. Removing it, well, agreed, that might be interesting.

The Concrete with a tight fit epoxy will provide a lot of strength and vibration damping. I need to check however, on the 4KW spindles, the pictures show that there are no 'lips' on any of the structure, so it can be removed once cast (lets assume its greased or similar). If it has a diameter larger anywhere, this will be the minimum I can do which means that the concrete is just there to provide overall damping and strength to the plate.

An idea that was provided was to cast the hole to the smallest possible. If I wanted to use a BT30 setup (I have one drawn), having a few mm spaced on the sides is not a major problem, just dont get the full benefit of the concrete.

For me, I love the idea of BT30, I already have tools for this however Id like something that can do at minimum 12K too, so might go with a dual approach on this one.