The Making of a Grist Mill

This post should have been written about one of the most beautiful attractions of yesteryear…the mill pond and specifically the waterwheel it powered. Like the steam powered locomotive, the waterwheel has always fascinated the Ranger. Both of these motive power sources, using the power of water have been harnessed as amazing labor saving devices by our ancestors and changed the world in which we live. Even at my age (the south-side of seventy) I wish I could tell you about the experience of having a picnic and a refreshing swim or skating at the local millpond…oh yeah, I guess I could…remember Louie?

Alas, it is almost impossible to find a waterwheel still operating today. The turbine is now common for mills and you actually have to go looking to see them. There are still a few rustic old mills and their scenic ponds around to admire and enjoy. Thanks to Robert at Tyrone Mill, Dominic at the Mill in Campbellcroft (a work in progress), Mitchell at the Purdy Mill at Castleton and most recently, Jim at the Woodley Sawmill in Haydon for allowing the 2oldguyswalking to explore their properties and ask a lot of questions. When first writing about the old mills, I was most interested in the rustic old buildings and their owners and their effects on the towns in which they located. Okay, I admit I didn’t know diddly about what actually went on inside those historic buildings! Having now expanded my knowledge of mill operations from many sources, it is time to share.

A mill site consists of a water source, a means to convey this water supply to the mill, called a ‘headrace’, a waterwheel pit and the actual waterwheel. With all the above in place it also needs a system of shafts, gears and pulleys to drive the mill and a means of returning all this water back to the stream or a ‘tailrace’.

One of the most common type of waterwheel is known as an ‘overshot’ wheel’ which uses either paddles or buckets to catch water as it pours over the wheel and this causes the wheel to turn in the same direction as the water flow going over it. The overshot is relatively east to construct and will provide a fairly large amount of power per gallon of water. Its major drawback is that it is very difficult to regulate the water. As water exits the buckets at mid-wheel height, the backsplash creates problems for the miller to maintain the wheel’s R.P.M.

Another very common waterwheel was the ‘undershot’ which was basically driven by the current of the stream. It was also fairly easy to construct but produced minimal power and was used primarily by smaller mills. An unusual modification of the undershot was known as the ‘tub’ wheel which was basically an undershot turned on its side and placed within a circular box producing about 14 HP. This great system very often allowed for the ‘direct drive’ of the millstone without the use of expensive gears and pulleys.  William Hore’s first saw mill (1832) in Camborne was thought to use a ‘tub’ wheel to drive his ‘up- down’ saw blades. This allowed him a very small back- up of water and thus a smaller dam and mill pond.

Another type of waterwheel was called the ‘breast-shot’ where water entered at mid-point at the side of the wheel, turning it in the opposite direction of the water flow. This type of wheel would produce very little backsplash. Power generated by all of the waterwheels turned a system of gears, pulleys and belts which didn’t make the water easier to control but did allow the miller to regulate the power to the mill drive.

The early waterwheels were very limited in the power they could generate. In the 19th century the mill turbine was finally developed. Think of the turbine as a ‘small horizontal waterwheel’ with the blades enclosed. The main difference between the waterwheel and the turbine was the ‘swirl’ component or the movement (or how much) water movement it added to normal water flow, this allowed the turbine to be much smaller in size and produce a great deal more power. The miller could easily adjust the turbines speed merely by adjusting the control gate from the millrace inlet gate to the waterwheel.

The mill gears, shafts and pulleys were connected by a vertical shaft running through two millstones. The lower ‘Bed Stone’ was in a fixed position (if driven from underneath was called a ‘Drift Stone’) while the upper ‘Runner Stone’ rotated. Grain arriving at the mill would usually be stored on an upper floor in grain bins and dropped to the basement millstones by a chute. Grain was slowly poured into an opening or the ‘eye’ in the upper stone and ground between the two stones. The stones had grooves cut into them which allowed the ground grain to be directed out of them for further processing.   This processing would include the meal or flour being transferred back to the upper floors to be stored in a Flour Chest or Meal Bin. This meal would then have to be ‘bolted’ or separated into different grades of flour. The millstones had to be kept well-dressed or the pattern of furrows in the stones would become plugged and require more power to turn, a Mill Bill (mill chisel) was used to clean and sharpen (dress) them.

Alas, eventually the rustic old waterwheel powered mill began to decline with the availability of steam and gas engines. Few know that the steam engine, outside of pumping water out of mines was first used to power grist mills. William Hore, of Camborne required a large dam and millpond with a waterwheel to drive his (1850’s rotary sawmill and tub factory. A picture in the Illustrated Historical Atlas of the Counties of Northumberland and Durham, Beldon-1878, shows his new grist mill with a large steam smokestack with the mill pond no longer needed, drained.

A huge population growth and major expansion of grain crops forced the mills to switch to a more efficient process where grain was crushed between steel hammers (hammer mill) or large rollers rather than between two large stones.

Some early inventions associated with the grist mill and attributed to an American, Oliver Evans were the elevator, an endless band or belt with attached buckets to lift product from the millstones to the upper floors of the mill for processing. The ‘worm’ or ‘screw’ for the same purpose. The cooler was invented to spread and cool the warm meal before it entered the ‘bolts’ (sifter) thus allowing a continuous mill operation.

Thanks to Jim at the Woodley Sawmill, we hope to eventually assemble more information, history and pictures of an actual water-powered sawmill in operation. Stay tuned.

Regards, Ranger.

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