by Gyrobot, published
This is a fully printable flexible coupling without support. This type of coupling idea can deal with angular and offset alignment problems plus also end float issues.
Also provides a little bit of a lag, a sort of soft start between the connected shafts.
I realise that there are many variables required in peoples designs, (length, diameters, hole types etc), so the stl file provided is an example that people can print off. Please see the customiser version (http://www.thingiverse.com/thing:44078), which has superseeded this version.
EDIT: Treated a PLA printout to a Carburettor Cleaner bath to make it even more flexible. See http://www.thingiverse.com/thing:98268 for instructions. Uploaded new images to show greater flexibility.
UK based Thingiverser's can buy from Toolstation : http://www.toolstation.com/shop/Carburettor+Cleaner/p30713
And Amazon : http://www.amazon.co.uk/Tectane-Carburettor-Cleaner-400ml-Aerosol/dp/B0046B2TKS
Safety Data Sheet showing ingredients : http://www.siroflex.co.uk/PDF/TectaneCarburettorCleaner0021.9.DBA.pdf