On Monday this week, we had a sharp wind come from the south with the windmill facing north. The windmill began to adjust accordingly, but at some point that morning, the fantail mechanism failed, and we noticed the fantail spinning freely in the wind, no longer turning the windmill's cap as it spun. 

At first, we assumed the issue was once again the top gear box which was already scheduled for an oil change in July. However, when we finally got a lift up high enough to see what was going on, the problem turned out to be with the fantail's axle. The key holding the joint between the axle and the upper gearbox tore through the shaft until it no longer grabbed and fell out, causing the fantail to lose connection with the gearing. The image above shows the damaged shaft along with a diagram of how a keyed joint is supposed to look.

This same problem happened in 2020 as well, but it has only been an issue since the last major restoration to the cap frame in 2018-2019 when the windmill got it's new windshaft and had major repairs done to the main beams of the cap frame and fantail. 

The problem corresponds to the unlevel angle upon which the fantail sits. When the spars were replaced in 2018, they changed the incoming angle of the axle going into the gearbox. The pink line demonstrates the angle of the axle, while the green line shows the angle of the gearbox opening. If this connection isn't properly aligned on a level plane, it puts unnecessary stress on the keyed joint shown above and the gearbox itself. This explains why the keyed joint failed in 2020 and why the gearbox seals were worn out by 2023. 

While attempts have been made to shim the gearbox closer to level with the fantail in the past year, we believe the damage had already been done. As a result, the problem we currently face is repairing this axle so that it will last. A welded coupling will eventually fail, but we also want to avoid having to get a crane and disassemble the fantail altogether if we can. 

At this time, we're working with a local welder on the solution and hope to have this resolved next week. We are not anticipating high winds over the next few days, and the windmill can still be turned manually if needed. West winds aren't as common, so facing east is generally a good place to be and also makes the worksite accessible with the lift. 

This does also mean that the catwalk will be closed for the time being. Anyone planning tours of the windmill will not have access to it until the repairs are finished. We will provide another update when the repairs are complete.

We also realize this isn't a conventional update, but we as an organization believe our members deserve clarity on issues the mill encounters and how we go about solving them. We believe we have a permanent solution to this issue which will eliminate the need for these kind of emergency repairs every couple of years going forward.