Restoring an Old Bell Hub Aermotor Windmill

by Kevin Moore

Good Luck

My grandfather always said that he would rather be lucky than smart or good looking. I have never been told that I was good looking, but I’m sure I have been told a number of times that I’m not very smart. I guess that means that I’m bound to be lucky.

The Lucky Find

The Aermotor Bell Hub windmill was literally rolled into a ball when we found it. A tractor had dragged it about 500 yards. I don’t know how they did it, but the tail had been pulled completely around between the spokes.

So What’s a Bell Hub?

The first time you see an 1897 Model Pumping Aermotor windmill, you will see why it was nicknamed the Bell Hub. The large hub looks just like a bell. This hub was only used for a short time and is very distinctive.

First Things First

I first took photographs of everything. Later, the photos would prove to be helpful in recalling how the windmill went together. I then sprayed penetrating oil on all the bolts and nuts.

As I waited for the oil to soak in, I started to search for other parts. Reminding myself not to focus on the main windmill, I looked around for parts that might be hidden in the grass or dirt. I’ve been told that the little parts can be the hardest to find replacements for later on, so I made a careful search of the area. While searching, I uncovered a number of parts a few yards away.

Taking apart a twisted 100-year-old windmill can be hard work. Trying to reach inside the bell hub and hold the bolt head was an ordeal. Everything was so twisted it was difficult to work with. I avoided the temptation to start cutting off parts. I’m glad I didn’t cut anything, as I needed the old parts as patterns to make replacement parts.

AJ’s Law

My windmill friend AJ had told me to “take everything” when I find a windmill. My daughter wasn’t familiar with AJ’s “take everything” rule, and made a reference to ending up with a windmill junk pile. I corrected her, telling her that at worst, we would have a historical “windmill resource facility.”

Now What?

You should also remember something else my grandfather told everyone. Whenever I helped my grandfather work in his shop, he would say, “Having Kevin help is like having my two best men not show up for work that day. Everything takes twice as long whenever Kevin picks up any tools.”


After power washing the windmill, I took more photos of it and started to take it apart. Upon disassembly, I found out the hard way that the pitman bolt on the large gear has reverse threads. The hub was in good shape, but the main shaft was bent and the Babbitt was worn through.

Don’t Break the Hub

I wasn’t looking forward to getting the shaft out of the hub. It was held in place by a wedge key and 100 years of use. The bent shaft didn’t help.

I ground off the end of the shaft and then put it in the press. Next, I made a jig to slide down over the shaft so I was pressing on the hub at the connection of the shaft. It didn’t move.

I applied more pressure and heat and it still didn’t move. The more we pushed, the more nervous I became. I needed a new plan before I broke the hub.

We put the shaft in a lathe and slowly milled out the center of the shaft. The idea was to provide a relief point for the keyway and shaft. Hopefully the shaft would collapse inward as we pushed. It worked!

Fold Slat A into Slot B

I had one V arm that wasn’t bent too badly, so we made a jig out of scrap metal. We followed the original arm as closely as possible, using flat stock. It took a while to get the jig just right. The V arms bolted into the hub at an angle and twisted slightly.

Some Assembly Required

After sandblasting, all the windmill parts needed to be painted. I found that heating the parts in front of the wood stove helps the paint stick. Here is another tip: Don’t let your wife come home and see you cooking windmill parts when you told her you would be cooking dinner.

Babbitt Time

I ordered the book “How I Pour Babbitt Bearings” by Vince Gingery. By trial and error, I ended up with a good pour. I repaired the pins with epoxy, as noted in my article Repairing an Old Aermotor Windmill

Honor Past Craftsman

At some point, someone replaced the original metal pitman arm with a wooden pitman arm. The workmanship on this wooden arm is outstanding. I felt obligated to replace the wooden arm with a nearly identical wooden replica. A friend, who is a true craftsman, took the dog-bone shaped part home and returned the next day with an identical wooden arm. I added bushing and thrush washers.

Although it went back together much easier than it came apart, it still took a great deal of time. I made new shafts and milled or drilled each connection or washer to provide a smooth running windmill.

I also added grease fittings so I can lube the windmill with a grease gun, and scratched the Babbitt from the point of the grease fitting to allow grease to flow down the shaft.

Tin Time

The Aermotor windmill tail vane was the old style swallowtail with black lettering, so I spent a great deal of time restoring it. The wheel required replacement.

I put the used Aermotor windmill wheel on in the shop just to test it out. I’m sure glad I did test it, because there is no way I could have done it on the tower! It seemed like everything was about half an inch out of alignment.

I found that my replacement wheel was out of round and the V arms did not allow for any movement. After a windmill wheel adjustment and careful alignment, I slowly tightened it up.

What Happens When You Pull This?

The Aermotor furl system was not together when I found the mill and I didn’t have a clue as to how to make it work. After laying it out on the kitchen floor twenty times, I finally realized I was missing a part. A few e-mails later, I made a furl disk that worked.

Slap It Up!

I was able to salvage the top few feet of the original tower; we just added a little angle iron and put it up. A small adjustment to the furl system was needed, but all in all, it went well.

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