looking for a coupling

[Jonathan]

Yes they are...used to sell them on eBay then decided it's just not worth it. They look like 8mm ones. For your size I would use 30mm aluminium bar, how long?

Here's some more I made earlier:

[Scott]

about 80mm long want good contact area both ends

will 30mm bar have anough meat left on the 16mm end for the screws ??

[Jonathan]

i need one for an 8mm and 10mm shaft sharpish if you have one handy jonathan pm me.

I can make one soon enough, message sent.