Great fix for the U-Bolt. I was having a weird resonance issue caused by the way the U-Bolt connected to the Y-carriage. I swapped to Mitsumi bearings thinking I had a bad bearing, grease packed PTFE and the noise still persisted. I adjusted the U-Bolts no less than 4 times and it was still making noise especially when it was jogging.
I decided to give this a try and printed in eSun PETG at 20% infill and it came out great with no supports. Fitted them in and the resonance noise is gone. Great model. The bearings snap in and held snug and then you use a 10mm M3 into the nut slot. There's enough material to create a firm fit.
I would have liked the nuts a little deeper down to give it more to pull up on but the main stress is on the Y-Axis belt mount and not on the bearing mounts.