This work has been contracted out to Møllebygger Petersen ApS, a Danish millbuilding firm that specializes in mill reconstruction and restoration. One of their lead technicians, Erik Batenburg, visited Elk Horn in September 2023 to conduct a thorough inspection of our mill and formulate a plan for the work needed. Erik will be returning this Fall with another associate from MP to complete the projects listed below. Møllebygger Petersen's has a special mission in Denmark to restore Danish mills and train people how to use and maintain them. We're especially be glad to be working with them.

The Mechanism

On a Dutch-style windmill like ours, the mill body has a cap or hat that houses the core mechanical components for capturing wind energy including the windshaft and brakewheel. For a better visualization, refer to the diagram here. 

Since wind direction constantly changes, a windmill needs to be able to turn itself into the wind. Traditional Dutch windmills, including the classical ones built in Denmark, were manually steered using a triangular yawing mechanism. Over time, more Danish mills proceeded to replace these with fantails, like the one on our mill today, which turns the mill into the wind on its own. As part of either system, the 20-ton cap and wings rest on a series of iron sliders which move about an iron track around the cap frame. These sliders, pictured on the right, are bolted directly into the white oak frame and the track is routinely cleaned and greased to ensure ease of movement. 

The Problem

It takes several years for a new cap frame to dry. As moisture gradually escapes the timbers, the wood shrinks and moves. As a result, regular maintenance is critical in the first 10 - 15 years of a new cap frame to ensure adjustments are made as it dries and settles into place. 

In our case here, as the frame has shrunk, the iron sliders now ride too close to the inner rail of the track. As the cap turns towards the wind, this causes the sliders to ride up the rail and slam back down. The excess force required to move the sliders puts increased stress on our gear boxes and the cap runs the eventual (and extreme) risk of popping out of the track altogether. 

The Solution

As scary as this problem may sound, it is a routine issue with new mill construction and one that Erik has plenty of experience in dealing with. Our first task this Fall will be to move all 12 of the sliders back into the track by less than an inch. This process involves disabling the fantail so that the mill will not try to move, and then jacking up the cap frame so that the iron sliders are suspended and accessible. They will then be removed and milled or adjusted into proper position and reinstalled. 

The Mechanism

The windshaft is a solid piece carved from a single timber of white oak that is over 10 feet long and almost 2 feet thick. After drying and forming, it is bored with a steel rod for the shutter system, and one side is cut open to marry to the iron hardware that the wings attach to. The iron shaft is rounded and rests on a bearing carved from blue stone which is kept greased at all times. To keep the shaft from splitting open over time, iron braces are clamped around all four sides, holding the shaft tight into place.

Opposite the wings is the brakewheel. To accommodate both, this part of the shaft is shaped square with 4 even sides. The brakewheel is pieced together with dowels around the shaft, making for an even and tight fit that can be shimmed as needed. This is where power is driven from the sails to the mill's internal gears. 

Our longtime supporters may recall this is the same windshaft we had installed during our Spin Campaign to get the new cap frame and wings installed. The lumber for the shaft was purchased in 2001, and stored at millwright Ben Hassett's facility in Virginia to dry. Hassett's crew installed the shaft in 2018 as part of our last restoration campaign. 

The Problem

If you have been inside the mill while it was running the last few years, you know the problem we're referring to. During operation, the windshaft crackles loudly with loud bumps and noises that echo all the way to the ground floor. It is unclear at present what happened, but Erik identified some issues during his inspection in September 2023. 

The noise is produced by micro gaps inside the shaft where different pieces come together. The noise makes it difficult to assess other potential issues with the mill during operation and if left unaddressed, will allow for excess and premature wear to the windshaft. 

The Solution

At present, it is unclear of what caused this issue and if it can be entirely fixed. Erik will work to disassemble the shaft this Fall and try to mend or at least improve its current condition. It is not uncommon for windshafts to receive repairs and even patches, and this does not mean the shaft has to be replaced. However, we will not know more until we can take it apart and get a better look inside. 

ADD A BRAKE CABLE

The Mechanism

The brakewheel inside the cap is more than a gear. It is also functions a brake to stop the wings or prevent them from moving. Our brake is friction-based, and an iron strap is suspended around most of the wheel along its edge. This strap is attached to a dried beam which hangs on a pulley. Lifting the beam loosens the strap, allowing the brakewheel to move freely. Dropping the beam tightens the strap around the wheel, causing it to come to a stop. 

Normally, the pulley that controls the brake beam is attached to a cable that can be controlled from the gallery or catwalk. This allows the miller to engage or disengage the brake without having to climb to the top which is both convenient and safer in operation. 

The Problem

The issue with our brake cable is simply that we don't currently have one. As a result, starting and stopping the mill requires climbing from the second floor up into the cap. This can be difficult if we need to access the brake in emergency situations, especially if we are running the mill during a festival or event that brings a lot of people inside the mill at once. 

The Solution

The brake beam's pulley will be replaced and adjusted so that a cable can be fed through the roof of the cap and down toward the mill's gallery along with the shutter cables. A new spring-loaded latch will allow us to confidently set or disengage the brake beam during operation. 

Everything else pertaining to the brake currently is in good condition. Having this feature will also enable us to have classes on how to operate the windmill as it is too difficult to bring a group of people up into the cap at one time. 

ADD A GREASE BANK

The Mechanism

A grease bank is a tubing system that allows the miller or millwright to apply grease to several points in the structure of the mill's cap and fantail from a central location inside the cap frame. For each zerk to be greased, a separate tube is added to the system, which is pumped using a manual or electric grease gun. 

The Problem

Grease banks are modern innovations and not authentic, but they did grow in popularity during the 20th century among mills still in use. They allow for the lubrication of several mechanical joints in and outside the mill, especially the parts of the fantail which require some careful climbing to be reached. 

The Solution

Tubing can be constructed from common materials. The apparatus will be fabricated with custom arms to reach the spots inside our windmill and fantail and attached to a central hub. We will be looking into an electric or battery-powered grease gun to pump the tubing as needed. 

REPAIR THE SACK HOIST