Seed drill wheel hub job

My neighbour has a seed drill which has eight tires in the back. Those wheel are connected to a common shaft with four wheel hubs. Two of these were originally welded on the shaft and other two are floating to allow tightening the wheels in place.
For some reason the welded wheel hubs came loose and the wight tires were not rotating with bearings as intended but over the shaft which was badly worn. The wheel hubs were damaged quite badly as well in the process.
I will now straighten the wheel hub center holes.

In this video I am using:
- Schaublin SV-51 (1955) Milling machine

I know you are not asking a question about why this failed. If all the wheels are on a common shaft, when the seeder goes around a corner there will be a big differential in what speed the inner and outer wheels will want to turn. This may cause unwanted stress on the welds. If you agree that this may be a contributing factor to failure a minor redesign may be required.

Steve

Quote:

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Originally Posted by Reidy41

I know you are not asking a question about why this failed. If all the wheels are on a common shaft, when the seeder goes around a corner there will be a big differential in what speed the inner and outer wheels will want to turn. This may cause unwanted stress on the welds. If you agree that this may be a contributing factor to failure a minor redesign may be required.

Steve

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Steve, we were talking about this design failure with Robert. They repaired the welds a lot stronger with weld bevels and all.
The seed delivery mechanism is driven by the wheel so at least other half must remain connected to the shaft. The other four wheels could be floating but then there is a possibility that a bumb in the field lifts the driving wheels off the ground and no seends come out.

Hopefully the fix works and it is not a problem. What I have seen on some with a wheel on each end is the "drive" wheels drive against and protrusion on the shaft. What this allows is if the outer wheel drives the shaft faster than the inner wheel wants to turn when going around a corner, the shaft can spin faster than the wheel.

What also may help is just having the four center wheels welded to the shaft. That way the speed differential between the drive wheels won't very as much.

Hopefully your welding of the wheels is not stronger than the torque the shaft can transmit.

Steve