Farm Collector

How to Build Windmill Fans

A  year or so back, Lowell Devries from Historic Prairie Village museum near Madison, S.D., asked if I would build a set of fans for a Baker Monitor Vaneless Model L windmill there.

I told him that as soon as we had another three-day blizzard, I would make him a set. Well, around Christmas 2009, we had one. By then I had two sets to make: One for Prairie Village, and the other for a Pipe Raymond that we had gathered up for our museum.

Bill Lee, curator at the Ag Heritage Museum on the South Dakota State University campus in Brookings, came up with an extra set of Pipe Raymond fans (with hardware) that he donated to me. Generally, fan hardware is lost, buried in the dirt where the mill fell or was dumped. Scrap dealers pick up the large pieces, but small pieces are lost under the grass. Dan Benjamin, Freeman, S.D., deals in old mills. He had parts I needed for the Pipe Raymond, and I had some parts he needed, so we both came out ahead with no money involved.

The right saw blade

Building fans is not a complex process, nor are specialized tools needed. The most important item to have is a 3/4-inch-wide blade (with three to four teeth per inch) for your band saw. When re-sawing, a wide blade keeps the cut going straight as it runs into the wood’s grain (photo 1). This cut is not smooth, but no one will be able to tell that, looking up 30 feet or so. The idea is to get five blades from a blank (more on this later), ending up with just a shaving left over.

Blades can be made from almost any wood. Years ago, cedar, cypress and redwood were commonly used, but some manufacturers used fir to save money. Most builders dipped fan sections in white lead-based paint a time or two to preserve them. When you find an original fan section, the paint is often thick where it puddled after being dipped.

Creating a guide

Blanks are made by cutting a 2-by-6 on a diagonal (photo 2): Make the narrow end 1-1/2 inches wide and that ensures a width of about 4 inches on the wide end. If you cut the first pair carefully, you’ll have blanks to use as guides for the rest. Nailing a cleat on the pattern blank will keep everything in line as you saw each 2-by-6.

The saw blade for the circular saw cutting slots has a kerf of just under 1/4 inch (photo 3). Getting blades the right width is a cut-and-try operation. Use scrap through the band saw and adjust the fence until the blade section will go snugly into the slot. If it’s too tight, you’ll break off wood between blade slots.

Secure the blade support wood in the jig (photo 4) and measure the radius of the old fan to get the center point for the saw guide. Measure blade spacing as well, marking each on a board beyond your saw, so as to move the saw guide from mark to mark when making cuts for blades. Fans are cut on a radial pattern: Some use smaller radiuses than others even though blades may be the same length (photo 5).

Built to last

If you want the unit to last, use galvanized nails. Pre-drilling before nailing will prevent cracked blades. When the fan sections are finished, install hardware and paint or treat the wood with a wood preservative, and the mill should last 20 or 30 years.

As to assembly: Baker used steel spars between sections, which made measuring easy. On the Pipe Raymond, all we had left was a semi-rotted, twisted oak spar. I guessed a little long, so I took up the slight extra diameter by using a shim (3/8-inch plastic washer) on each blade at the pivot (photo 6). If the fan sections aren’t tight, they’ll bang as they slide back and forth on the pivot rods when turning.

Surviving the storm

Our largest wood fan rebuild was a 12-foot Elgin at the Western Minnesota Steam Threshers Reunion in Rollag. Shortly after we installed the finished piece, an 85 mph wind rolled through the grounds, taking roofs and doing damage. We had permanently furled the mill, however, and it came through unscathed.

Just as happens today, some old-line companies sold on quality and some on price. Baker made good quality wood fan mills and, later, good steel self-oiling windmills. The Pipe Raymond, on the other hand, is a rather competitively priced unit, simply and cheaply constructed. But, like other less-than-perfect relics, it is a piece of history that needs to be preserved. So it goes. FC

Jim and Joan Lacey operate Little Village Farm, a museum of farm collectibles housed in 10 buildings at their home near Dell Rapids, S.D. Contact them at (605) 428-5979.

  • Published on Apr 21, 2010
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