So this happened today - banditt stump grinder

[DST0922]

For all I know this is a common occurrence, but from the reaction I rm received from banditt I doubt it. While taking out a row of small stumps, I noticed the "upper unit" seemed shaky. Shortly after the whole upper unit shifted and started to fall off to the left (while the grinder wheel was engaged). I was and to shut down the wheel and hold the upper unit in place until my guys were and to strap it into place. It appears every single bolt on my turntable or slew ring either fell out or sheared off. If you look at the pictures, that top ring is supposed to be aligned with the bottom ring. Curious to know if anyone else has had this issue.

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[swaney]

That's terrible. It seems like all these companies have a quality control problem/issues. That should have never happened, hope no body got hurt as this could have been devasting.
Hope they correct everything soon for you.
Swaney

 

[sgbotsford]

Bolts come in various grades. There are marks on the head. 3, 5 and 8 are the most common. Marks described here: https://www.boltdepot.com/fastener-information/materials-and-grades/bolt-grade-chart.aspx

If someone used grade 3 instead of grade 8 bolts, they would have about 45% of the use. Still to me, not an adequate margin.

The next possibility would be that they didn't use a nut lock to keep the nuts on in a very vibration prone environment.

I suppose it's possible that someone used a 'too small' bolt too. But that would be *really* careless.

Anyway: When replacing:
* Use grade 8 bolts.
* Use the largest one that will fit the holes.
* Use locktite or similar (use the grade that can be heated to remove....) to keep the nuts in place.