Well for a start as you have said in your post the Triac is a milling machine so it won't turn.
The Boxford Duet is basically a training machine and as such is at home making tiny parts out of machining plastic, alloy parts are not really suitable for a machine such as this.

Without knowing better just what alloy parts it's hard to recommend anything but a Connect lathe, based on a Myford ML10 or the Denford Orac are far sturdier machines.

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