Having received some sub-standard shaft couplers for a CNC conversion I'm now thinking about making some rather than waiting another 4 weeks for replacements.
Is there any particular advantage to the fully spiral (like a spring) kind over the easier to make alternating slot type? It would appear that the spiral kind are usually made from aluminium and the slotted kind is usually used with harder material such as stainless etc. I don't know why this should be the case.
At the moment I only have a (manual) rotary table, a vertical mill with a single motorised X axis (Y and Z need the couplers) and a Dremel cutting disk which can do deep cuts into bronze.
Mike.