After having the bolt snap on my cable chain I rigged it up so I could print the repair part. I found that the M3 bolt was loose in the cable chain and could be tightened up so that the cable chain couldn't move.

I modelled this simple sleeve to allow the cable chain to sit securely and you can't over tighten the bolt.

I used an M3x20 bolt and put a dab of locktite on it for good measure