Mills as Giant Tools

by adminpower

Have you ever been to a mill? There were saw mills and woolen mills and grain mills and more. They were basically huge tools or machines. Nowadays they have been shrunk and a combine going along the field basically does most of what a mill originally did.

At first, they were all water powered and then later many switched motors. Some later used turbines powered by the water flow instead of the water wheels. The water wheels always had a direct mechanical linkage. The turbines which were more efficient than the water wheels could be also set up with a direct mechanical linkage. Or they could be used to generate electricity to drive motors to drive the machinery.

If you have never been to a mill, you should. They were a marvel of 1700s and 1800s engineering. And you wouldn’t believe how many there were. On the US East Coast there were thousands of them. In Pennsylvania alone there were almost 2,000 of them. Possibly more.

Interestingly many were on fairly small streams and creeks leading into larger rivers. It took a bit to get the water wheel turning, but once started, it didn’t take much water to keep it going.

When a farmer would come to the mill with a wagon of grain to be milled, it would be typically be hoisted to the top floor. That is why with most mills you will see a large beam extending out from the peak of the roof with a pulley that was used to hoist the grain and any equipment and supplies they needed on upper floors.

They then made use of gravity and as the grain was processed it normally moved down through the mill. One of the first things that would be done was to put it in a separator. The amazing thing is that these have changed little in design over the last 150 years. In fact, one company said they still use the same size screens as they did in the 1850s. So if you have an antique separator, you can buy a screen from them and it will fit fine.

The separator has shafts that are rotated by whatever power source is currently used. The shafts spin a blower and also a shaker. The grain goes on top of a larger screen. The grain and smaller contaminants drop through and the chaff and larger particles are blown away. Typically they would be blown down a tube and out one end of the mill, usually over the river. A biologist said that that this practice significantly changed the ecology of the river around the mill.

Then the grain lands on a smaller screen that is too small for the grain to fall through but dirt and weed seeds fall through and are carried away, leaving just the grain.

Then the grain would be taken down to the mill wheels to be ground into flour. Then the flour would be bagged or boxed and moved down to be shipped out.

Over time different devices were invented to make the mill work less labor intensive. A major inventor in this regard was Oliver Evans. His mill, Greenbank Mill in Delaware still operating as a museum. Besides revolutionizing how mills worked, he also other important inventions, in particular the high pressure steam engine.

Going to one of these mills and seeing what they did with wood and iron is rather incredible. Today it looks clunky and antiquated but at one time it was cutting edge technology.