pic: Hex Bearings

[Tungrus]

The failure may be due to 1 in a millionth chance that it was manufacturing defect (nothing is perfect) but its not common. In past 4 years we have been using both AndyMark as well as VEX bearings on drive and other systems. Never had this issue. We have 7/8" bent aluminum shaft, 3/16 hollow steel shaft but not the bearing.

Looks like both VEX and AM have/are releasing super-bearings this season. Price will stop me from going to these new super bearings.

[Aren Siekmeier]

Originally Posted by Tungrus

Looks like both VEX and AM have/are releasing super-bearings this season. Price will stop me from going to these new super bearings.

The Andymark bearing went up $1 to $6, but the Vex bearing is the same price as before, $5.

I imagine the failure has something to do with the torsional load seen in 1678's flexible intake arms. Our intake this year had similar flexibility, and when it deformed our intake roller stalled more easily due to the load on the bearings. In a WCD, the load is almost entirely radial, since the double bearing arrangement takes up the torques from the cantilevered wheel and the chain.

EDIT: What Frank said.

[Richard Wallace]

Originally Posted by Aren_Hill

Well, larger inner race, so yes, that does mean smaller balls and more of them.

Thanks for clarifying, Aren. I could not tell if the inner race was enlarged radially or axially, since there is no pdf on your site yet and I don't have CAD on my tablet (yet).

[Michael Corsetto]

I will confess, we should have turned the end of the shaft down to 1/2 round and avoided using a hex bearing in this particular setting. Lessons for next year...

[PayneTrain]

Originally Posted by Michael Corsetto

I will confess, we should have turned the end of the shaft down to 1/2 round and avoided using a hex bearing in this particular setting. Lessons for next year...

secrets secrets are no fun unless they're shared with everyone

We wrecked 3 or 4 bearings this year and I had assumed it was due to bad implementation. It probably still was, but it's nice to know about new and improved hex bearings we can buy to fashion a throne alongside the 3 ft pieces of 1/2" hex shaft y'all sell.

[magnets]

The failed bearing on the left confuses me.

My experience with hex bearings is that they are hit or miss in terms of quality from all vendors. None of them roll as smoothly as the comparable round bearings, and they have varying degrees of accuracy with runout and hex sizing.

Generally, I'd try to avoid them if it all possible. Even if you think they're strong enough, dealing with availability and variation between suppliers can be frustrating.