Windmill manufacturers were plentiful back when those wind machines helped pump water on many American farms. Windmills could be built by nearly anyone, provided they had access to a foundry, a place to cut the vanes and spars and nail them together – and a market to sell the wind catchers. When pioneers moved west into more arid lands, the windmill manufacturers followed, and companies such as Aermotor in Chicago, Dempster Mill and Mfg., Beatrice, Neb., and Challenge Wind and Feed Mill Co., Batavia, Ill., became large, successful windmill producers.
Surprisingly, even though they’re exposed to the elements year-round, windmills require very little attention. Ideally, the oil should be changed once a year, but I’ve taken down many that spun indefinitely and still have dark, thick oil in them -with tight gears and bearings. They’re a tribute to the builders who crafted the wind machines.
I’ve rebuilt a number of these old windmills, both open and direct-stroke mills, a couple of which I’d like to review for others who may have an old mill in their sights. The Baker Model L, a 10-foot-diameter unit, was built until 1940. The mill’s governor is constructed from springs that act on the arms, which connect to the fan sections. As the wind slows down, the springs pull the fan sections flat to expose more of the fan to the wind. In high winds, the centrifugal force causes the fan sections to fold in, exposing less surface area to the wind, which slows down the unit.
This particular mill showed very little wear in its linkages or in its bearings, but required new fan sections. I joined the new fans to the old hardware, and then assembled the whole fan. Although it may seem complex, fan blade fabrication isn’t mysterious. I merely measured wood from a pattern and cut the heavier wooden pieces with a table saw.
For the next step, I used a jigsaw to cut the fan blade slots for attachment. The process is fairly simple because the fans extend radially from the center. My fan blade slot width is about 1/4 inch. I take a cutting blade from my power saw and bend the teeth out both ways so it cuts the required slot width. Then I cut the fan blades on a band saw to get the same width as the slots in the heavier sticks. My fan blades are tapered end-to-end, generally from 4 inches to 1 1/2 inches. I taper my blades with a jigsaw. Ideally, blades should go into the slots with a little friction, and are then nailed in place with a piece of reinforced wood in a uniform manner.
The second woodfan windmill restoration we did last winter was a ‘Challenge Vaneless,’ also a 10-foot mill introduced about 1912. The unit is an early model since it has wooden arms that support the fan sections -later units came with a different front casting design and steel arms. Unlike the Baker restoration, the second windmill required major repair. All the ‘dog bone’ pivot linkages were worn oval and needed to be bronzed and redrilled. Also, the 7/8- by 1/4-inch flat control arms had to be replaced, along with the round rods, which control the position. Luckily, we had the castings for the ends of the fan sections. The mill had a rather hard-working governor arrangement, with a cast iron bearing and a very heavy counterweight that helps spin the mill at a constant speed. Like the Baker model, the Vaneless needed more grease. In spite of that fact, the main bearing was still good and had no excessive wear on the other pivot points. The main shaft’s oilers have no covers, so the oil seeps in and washes out.
To show off our handiwork, my son, Matt, and I took the finished mills to a museum and put them on elevated platforms and treated them with a water-seal finish to bring out the natural wood color. For those interested in reading an enjoyable book on windmills, I recommend T. Lindsay Baker’s ‘A Field Guide To American Windmills,’ a rather pricey book but well worth the money.
– Jim and his wife, Joan, operate Little Village Farm at 47582 240th St., Dell Rapids, SD 57022. Contact him at (605) 428-5979.