And I was aware of this when I bought the the Chinese Machine! but In my professional life I learned this and I was prepared
When I was installing and running the first tests with the wooden car the machine one of the Stepper Motor flexible couplings broke. I contacted the vendor an made the claim, and I am still waiting for the replacement part but I order 4 spare parts from other vendors of better quality expecting that this will happen again and it did!
I lost two pieces of good wood and a lot of time. Now I replaced all the couplers in the three Stepper motors and I order 3 more they cost $8.00
The Broken coupler and the new one:
New coupler installed on the three motors: