Need ideas (or someone to make) a widget to couple motor shaft to M8/M10 threaded rod

[HankMcSpank]

....turn down a threaded bar with bearings on each end and the last section tuned to 6.35mm so you can use a flexi coupler to the motor.

The problem with a bearing on both ends of the threaded rod is one of access...I need to get my hands in/out a lot (to wind the copper wire on to the main bobbin etc)...this is why if you look at my last photo (of my 'loosely lashed together up' design), I supported the threaded rod a few centimetres in from the end of the rod with a small bearing ....that keeps everything nice & clear/open for ease of access (& it's also easier to thread the copper wire under an open ended bit of threaded rod)