NOTE: The following is based on direct observation and on written and graphic descriptions contained in the following references:
1. PRACTICAL MILLING by Professor B.W. Dedrick, Head of the Mill Engineering School of Pennsylvania State College, First Edition, published by NATIONAL MILLER, Chicago, Illinois, and copyrighted in 1924.
2. THE YOUNG MILL-WRIGHT & MILLER’S GUIDE by Oliver Evans reprinted in 1990 by THE OLIVER EVANS PRESS, with forward by Eugene S. Ferguson, from the 1795 First Edition.
Around 1850, Lewis Turner and his carpenter son-in-law, Henry Hall, built a 28 by 20 foot dry stone foundation at the foot of the hill immediately to the west of their saw mill on Little Goblintown Creek and across the water wheel pit serving the saw mill. Within the deep front or northern half of this dirt floored basement they built a sturdy framework of heavy oak timbers resting on stone footings to support the bed stones of three sets of mill stones, bearings of a main power shaft from the water wheel, and pedestals for the vertical shafts carrying the runner stones above. Over this, they erected a two story frame building supported by the dry stone walls and a central post, and covered it with clap boarding under a tin sheathed roof. Nine six over six pane double hung windows provided ample light and ventilation for mill operations on both floors, and a shallow fireplace in the rear or south wall provided winter heat to the receiving and delivery area on the first floor. Sometime in the early 1900's, the middle set of stones was removed, and their bevel gears and pedestal below were replaced by a large pulley on the main drive shaft to take power by belt from a steam engine located on a concrete pad outside the front basement wall.
The Turner/Hall Mill processed corn, wheat, and buckwheat. It was a very modern
mid-nineteenth century mill powered by a large water wheel driving a mechanical power train. It’s
mechanization made operation by a single miller and perhaps a helper or two possible. We do not know its original detailed
layout, but from the extant post Civil War configuration the following is evident. As indicated in this schematic, raw grains, usually arriving in sacks,
were weighed and dumped through an opening in the first floor into a hopper in the basement at the bottom end of the
receiving grain conveyor which delivered the raw grain to a selector gate at its upper end above the second story.
This simple wooden flapper was positioned from the first floor receiving area by a wire bridle to route the incoming product
to either the corn cleaner or the wheat cleaner, both located on the second floor of the building. The corn
cleaner delivered cleaned kernels directly to the hopper of the smaller (42 inch diameter) set of mill stones,
the winnowed chaff to the outside of the building via a large duct, and heavier wastes to buckets. Ground corn meal was directly bagged and weighed for delivery. The wheat cleaner output was channeled to a larger (48 inch diameter) stone set, and
light waste was ducted to the outside of the building as with the corn cleaner. Ground wheat was ducted from the stones into the delivering grain conveyor which fed the bolter on the second floor. Finished flour and coarser "middlings" from the bolter were ducted down to the first floor where they were sacked and weighed for delivery or, for some middlings, cycled back for further grinding.
The following paragraphs describe each item of machinery highlighted above.
Water Wheel. The original wheel was about fourteen feet in diameter. It had a nominal 3 inch diameter machined
iron shaft and two cast iron hubs spaced 50 inches apart as shown in this photo of it resting on the concrete steam engine slab. Eight heavy oak spokes were bolted to each hub to support the
peripheral oak frame and buckets. An 8 segment, circular cast iron rack 8 feet in diameter with 136 teeth was bolted to the
side of the wheel next to the mill building. This rack engaged a pinion with 20 teeth on the outer end of the main drive
shaft. Tooth pitch was 2.25 inches, with pitch diameters of 97.4 inches on the wheel rack and 14.32 inches on the pinion. The gear ratio was 6.8 to 1. Water to the wheel was controlled by a gate near the end of the flume from the mill pond. This gate was operated by a lever through a slot in the first story mill house wall to control wheel rotation at about 10 revolutions per minute. The hybrid iron and wood construction of that wheel dates its origin to the mid eighteen hundreds.
Power Train. The nominal 3 inch diameter main drive shaft runs from the water wheel pinion into the basement
through an opening in the mill house wall. It now carries two 60 tooth bevel gears, one for each set of existing mill
stones, and two 36 inch diameter cast iron pulleys. It runs in 3 babbited pillow blocks bolted to the heavy
(up to 12 X 12 inches) oak timbers of the mill stone support structure. The driver bevel gears for the mill stones, one of which is shown here, are
iron castings with slots into which carved oak teeth are wedged. These mesh with smaller, 29 tooth, all cast iron bevel
gears on the vertical shafts turning the upper mill stones. The lower ends of these shafts have stepped combination journal
and thrust bearings. A shoulder on the bearing housing rests on lands on the end of a pivoted lever arm linked by lead
screw to a hand wheel on the first floor adjacent to its stone set allowing the shaft to be raised or lowered over a small
interval (about 1/2 inch or less). This allowed the miller to control the gap between runner (upper rotating) and bed
(lower stationary) stones. Spades or flat arms on the upper end of each vertical shaft engage slots in its runner bore.
The weight of the runner stone is carried by an iron yoke or "rynd" pivoted on the upper end of the vertical
shaft above these spades or arms.
A large pulley on the inboard end of the main shaft drives the secondary drive shaft in the rafters above the second story via a long leather belt 6.5 inches wide. As noted above, another pulley was added to the shaft in the early twentieth century in place of the middle stone set bevel gears to accept power via belt from a reciprocating steam engine mounted on a concrete slab outside the front wall of the mill building. The removed stone set had probably been used for spring and winter wheat which were more efficiently processed in a new roller mill a few miles away. The steam engine was probably needed because of a dwindling water supply. According to Mr. Lauren Via who worked in the mill around 1933, a wood fired donkey boiler provided steam for the engine. Others remember a Buick gasoline engine driving the mill from the same concrete pad in the late 1930's.
Secondary Drive. The secondary drive shaft, running at twice the speed of the main shaft , or about 136 rpm with nominal 10 rpm water wheel rotation, powers the corn and wheat cleaners on the second floor via pulleys and belts, and the tertiary drive shaft via sprocket and chain.
Tertiary Drive. The tertiary drive shaft, also in the rafters over the second story, runs at about 45 rpm or one third the speed of the secondary drive. It directly turns the power drum at the upper end of each grain conveyor, and the bolter via sprocket and chain. Sprocket diameters cause the bolter to run slightly slower than the tertiary shaft at about 35 rpm.
Mill Stones. Shown here are the two sets of existing stones. The primary set, in the left rear, consists of solid granite units 42 inches
in diameter, 9 inches thick, and grooved to handle corn. The other set, whose shroud has disappeared, is 48 inches in diameter and has not yet been lifted
for inspection. These larger units are probably built up of buhr stone segments cemented together, and finer grooved for
buckwheat. Buhr stone, quarried in France, is a form of silica; like flint in hardness, but less brittle. Such stones were
considered optimium for grinding wheat, and were the most widely used before roller mills supplanted stone mills. All
stones are backed by thick plaster of Paris padding which increases their mass, stability under load, and heat dissipation
characteristics. Lead balancing weights are buried within the plaster padding of each runner stone.
Conveyors. Shown here are the bottom ends of the two bucket conveyors which extend from idler drums in the dirt-floored basement to power drums on either
end of the tertiary drive shaft in the rafters above the second story. They are identical in construction. Wooden,
rectangular cross section ducts connect the idler and power drum housings, and contain a 4 inch wide endless heavy cotton
belt fitted with small riveted sheet metal scoops spaced about 14 inches apart. The receiving conveyor transports raw grain
from a hopper, in the background here, to a flapper valve at its upper end which routes product to either the corn
cleaner or wheat cleaner. A sliding gate at the bottom of the hopper and controlled from the receiving area on the first
floor allows the operator to start or stop the flow of grain from the hopper into the conveyor chanel. The delivering
conveyor, in the foreground, moves ground meal directly from the buckwheat mill stones up to the bolter.
Corn Cleaner. The corn cleaner is a size 1, one hundred bushel per hour unit manufactured by Sprout Waldron of
Muncy, Pennsylvannia (founded in 1866). It consists of a six arm paddle blower, winnowing chest with corn input and
discharge end gate valves for regulating air flow, a vibrating two section separator sieve, and a chaff discharge duct to
the outside of the mill building. It receives raw corn from the receiving conveyor through the right end of the chest cover, removes chaff to the outside air,
routes heavier debris smaller and larger than kernel size to buckets, and discharges clean corn to the feed hopper of the smaller set of mill stones directly below.
Wheat Cleaner. The wheat cleaner consists of a smutter, scalping shoe and cockle cylinder. It is a
"EUREKA SMUT & SEPARATING MACHINE", serial number 11479, manufactured by HOWES, BABCOCK & CO. of Silver
Creek, Chautauqua County, New York, and has a rated capacity of 10 to 15 bushels per hour. The upper section of the machine is the smutter which consists of a large wooden suction air plenum over a large horizontal paddle blower atop the smutter cage itself. A single vertical shaft turns the blower rotor and a set of blades within the cage. Incoming grain from the receiving conveyor drops onto a small two stage vibrating separator sieve before it is fed via a leg of the suction plenum into the top rim of the smutter cage. This cage is about 18 inches in diameter and 10 inches high. Screw vanes on the vertical drive shaft pump air upward into the cage. This draft, in combination with the vertical blades extending the full height of the cage, swirls and beats the incoming grain, throwing it against the stationary steel shell which is perforated by many closely spaced vertical slots. A segmented and removable wooden cover surrounding the shell forms a vacuum chamber on the lower suction side of the blower which sucks up the broken smut and chaff passing through the cage shell slots and blows them out of the
building via the discharge duct. Purged grain drops through openings in the smutter's spinning lower plate and into the output duct where it is further subjected to draft from the suction plenum as it drops onto the screen of a large vibrating sieve separator or scalping shoe. The "throughs" of this screen pass to the inside bottom surface of the rotating (at 15 to 20 rpm) cockle cylinder . Non-through material dumps into a sloped, vibrating trash tray running the length of the cylinder a few inches above its bottom surface. The conical cockle cylinder is 61 inches long, with diameters of 20 inches at its input or head end to 25 inches at its tail end. Its axis is tilted down head to tail such that its upper edge line is horizontal. Its sheet metal shell is uniformly and densely dimpled, with the dimple cavities on the inner surface of the shell. These shallow depressions pick up ball like contaminants in the "throughs" such as cockle, wild peas and mustard balls, and carry them up with the rotating wall until they fall by gravity onto a stationary apron extending from head to tail close to the wall and a few inches above the bottom of the drum. This sloped apron dumps into a sheet metal trough fixed to the vibrating trash tray. Materials moving down the trough join the trash tray contents at the tail for discarding. A fixed brush further up the wall sweeps any carryovers back to the apron. Oblong particles such as wheat or barley kernels are not caught up by the indentations, or if they are caught quickly fall out before reaching the apron, which may be adjusted depending on the grain being processed. Cleaning grain travels in a swirling, washing motion down the sloped bottom of the cylinder as it turns, to spill from the tail into the stone hopper below for grinding.
Bolter.A bolter is a rotary strainer that performs the same separating or grading action as a flat screen or sieve. The Turner/Hall Mill unit shown here was manufactured by the Salem Machine Works of Salem, Virginia, shortly after the company was founded in 1866. It consists of a frame structure of wooden timbers. Overall, it measures 115 inches long, 60 inches high and 34 inches wide, and has a flat top of tongue and groove boards. A 1.5 inch diameter iron shaft with sprockets on either end extends the length of the device. Fixed to the shaft by three sets of iron spider arms is a wood framed drum structure 85 inches long and 26 inches in diameter. This drum was covered with fine white silk cloth, only a few swatches of which remain. Most probably, the mesh of the head half of this cover was very fine to pass flour, and the tail half courser to pass a lower grade flour or "middlings". Short cast iron screw vanes on the shaft at the head and tail ends of the drum move incoming meal and outgoing refuse to and from the drum core. 12 wooden slats with an L cross section run the length of the drum an inch or so inside the skin. These are called "carriers", and are skewed relative to the drum axis to impart a head to tail (left to right in the photo)
drift of meal within the drum. Running along the upper outside length of the drum on the down-going side is a rotating brush
with two rows of long soft hair bristles which sweeps the mesh skin clean of carry over as the drum rotates past it. It is driven by sprocket and chain from the drum shaft on the tail end of the machine. Along either side of the base below the drum are two wooden screw conveyors on iron stub shafts driven by sprocket and chain from the drum shaft at the head end. Flappers between and above them are positioned to drop sieved product to one or the other. Both move their contents from head to tail ends of the machine, but either may be reconfigured to move product from tail to head. Each discharges to a gated duct on the floor below where product was sacked for delivery or recycling. Removable panels enclose the sides of the drum space between the machine’s solid end walls to contain flour dust. Canted slats on the inside surface of the drum's tail end wall carried refuse into the tail end shaft screw for discharge via the sloping duct shown.
Other Equipment. What is believed to be the original flour bolter of unknown manufacturer was stored against the front wall of the second floor of the building out of the way of mill activity. It was probably replaced by the more modern machine described above when the mill was improved sometime after the Civil War. Similar in construction to that bolter, it measures 101 inches long by 48 inches high by 29 inches wide, with an 18 inch diameter drum 88 inches long. Its drum contains a solid walled inner cylinder of about half the drum diameter. This cylinder has narrow lands or ribs on its outer surface which cause it to act as an agitator. The drum is covered with steel wire mesh, fine over the head half and coarse over the tail half . The sievings fell into two screw conveyors feeding output ducts as with the bolter, and refuse exited through the tail end wall. A broken conveyor screw is resting on top of the machine in this photo. This machine has been completely disassembled and removed from the mill building. It is being restored for display in a small museum on the mill property.
