After 118 years of operation, one of the water turbines at the Ressler Mill needed to be refurbished. This article describes the project engaged in 2024/25 to remove, refurbish, and replace the turbine.
The Ressler mill employs two turbines, an 18” S. Morgan Smith turbine powers the corn (feed) mill and a 24” Fitz-Burnham turbine powers the roller mill (flour) side of the mill. Jacob Ressler replaced the older, overshot water wheels with these turbines in 1906. The mill has been in more-or-less continuous operation through 1977. Since that time the mill has been open as a museum. The museum operates Tuesday through Saturday from May until October. The guides operate the turbines as part of the tour.
During the 2024 season, the guides noticed a decrease in power on the flour side of the mill. The roller mills would not come up to their operating speed. The millwright postulated several ideas about what the problem might be. It could be a leak in the case, or debris stuck in the blades or some other issue. The only way to find out was to drain the penstock and examine the turbine visually. The penstock is a large, concrete cistern with a wooden bottom that holds fourteen feet of water. Both turbines rest at the bottom of the penstock.
The first step before draining the penstock is to lower the head gates to prevent water from entering through the head race. Here is a view of the head race with the gates lowered.
Then, the penstock could be emptied by opening the gates on both turbines and waiting for the water to drain out into the tail race. In the interest of safety, the team stopped the water at the dam and drained the entire headrace while there were workers inside. Once that was completed, the workers found another problem. The bottom of the penstock was filled with nearly a foot of sediment.
Here is the top of the S. Morgan Smith turbine nearly buried in sediment.
Here is the top of the Fitz turbine, likewise partly buried.
How would they remove that sediment? Would they have to hoist it out in buckets? There were rumors of a hatch in the floor of the penstock, but where was it? After some poking around in the mud, the workers were able to locate the hatch. Here are the workers, down in the penstock, opening the hatch for the first time.
The next photo shows the penstock with most of the sediment removed. The S. Morgan Smith turbine is in the back.
Finally, the Fitz turbine could be viewed directly. The result was not encouraging.
The register gates that open and close to control the flow of water were severely corroded and partially blocked with rusted metal. This was preventing the gates from opening fully, which explained why the turbine wasn’t providing full power. The bolts holding the case together were rusted solid. The team decided that the best option would be to pull out the turbine and take it to a shop to be refurbished.
Perhaps refurbishing is not the right word. The major pieces of the turbine were newly forged at a local foundry. The next photo shows the partially completed mold for one of the registers. The mold was formed in sections and placed in the sand.
Here is the finished product.
The following photo shows all the new parts. The new cap is in the foreground, the runner is in the middle, and the inner and outer registers in the back. They also made a new bracket to hold the lignum vitae bearing that supports the runner in the enclosure.
Here is the reassembled turbine sitting outside the mill waiting to be reinstalled.
The team plans to reinstall the turbine later in July provided the creek is not too high from all the rain we had this year. For more information about the Ressler Mill (aka Mascot Roller Mill), see their website at https://resslermill.org/