The Y axis coupler on my cnc router has snapped.
It is/was a flexible coupler. The stepper motor has a 1/4" shaft and I have seen similar couplers on ebay etc. But not exactly the same. My coupler has two grub screws at each end, which clamp the coupler to the shafts. The stepper motor end is a plain hole but the screw end is threaded as well as clamped. I'm not sure what the thread is, but is around a quarter inch.
Ideally I would like to source the exact replacement and as quickly as possible, but would I be safe in buying the standard flexible, zero backlash, quarter inch/quarter inch available on ebay? I don't like the idea of clamping onto the threaded end of the lead screw.

Any suggestions would be appreciated.

Dave