I work for a manufacturer of large scale equipment with high vibration. We use 8.8 and torque to a lower value than industry standard on our installations. We have found higher strength bolts actually break more frequently.
Not saying it’s apples to apples, but “stronger” isn’t necessarily better.
There’s definitely something unique going on. The load on that bolt has been engineered and it’s of similar size as every other modern sled out there. It’s not rocket appliances.
Harmonics? Clutch slipping and tightening the bolt? I think we’re past a qc problem of the bolt.
Buddy thinks it’s the loose outer sheave.
The bolts are also custom to this application. You can’t just get a higher grade one from a supplier.
Stronger generally means more rigid like you said which isn’t always good when you require some level of ductility if the harmonics are off. I’m curious if any one has pulled a used bolt and compared it to a new one. I’m talking micrometers and verniers. See what’s the difference. I’d like to see pictures of the broken bolt ends as they tell stories too.
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