RCAHMS Threatened and Industrial Buildings 2007

Date November 2007

Event ID 608846

Category Recording

Type Standing Building Recording

Permalink http://canmore.org.uk/event/608846

INTRODUCTION

In August 2007 RCAHMS was approached by Historic Scotland regarding the Firth water-powered grain mill at Finstown, Mainland, Orkney. The building had recently been bought with the intention of conversion to a dwelling. There was a considerable amount of surviving machinery at the site. There was also recognition that the building would be altered, at least internally, as a result of its new use and that there may be potential loss. RCAHMS already had some information on the site (MS/500/35/22), which included a draft layout sketch, but not enough to remove the need for a survey. The building is B Listed and so fell within the remit of RCAHMS Threatened Buildings Survey. Survey work was carried out in October 2007.

BACKGROUND:

Built sometime before 1854 (1), Finstown grain mill is a good example of the Orcadian type and is situated on the NW edge of Finstown in the parish of Firth on the Orkney mainland, approximately 9.5km NW of Kirkwall. This mill produced bere meal, oatmeal and animal feed (or chop). There was some alteration to the kiln block in 1942. The mill closed in 1955 (2).

The mill is a two-storey and attic rubble-built 19th -century block in an ‘L’ plan with a flagstone roof. There are at least two distinct phases to the structure: the earlier W range housing the milling machinery and waterwheel transmission, and the E range containing the storage and handling area and kiln. The principal entrance to the mill is at ground level on the SE elevation of the main mill building (W range). In the SE elevation, there is an entrance into the storage area at ground level and a blocked entrance into the kiln area to the E. The kiln roof is of corrugated iron and may date from remodelling in the 1940s.

WATER SOURCE

Water for driving the waterwheel was drawn from an E running burn with its source at Loch Wasdale (HY 3426501481) and water flow regulation sluices at HY34195 14507 and HY 34245 14210. The water was impounded by Millquoy mill dam (see DC51296, A) at HY35388 14174 and was in turn led by a lade (B) to the mill wheel approximately 110m away. The millpond is now approximately a third of its original size (3). The water from the wheel tail race discharged into the Ouse and thence into the Atlantic Ocean.

The mill dam is of rubble construction with a packing of loose rubble and earth. The dam retaining wall to the S is of concrete (C). At the NW end of the dam wall, flagstones have been placed on end and sunk into the ground to reduce attrition of the overflow area (D). The front of the dam (E elevation) is buttressed with earth. The sluice gate, which is no longer in use, is still in situ at HY35400 14158 (E).

The lade (B) leaves the dam as an ill-defined channel (F). This becomes stone-lined at HY35415 14166 and continues as such until HY35432 14176. From HY35432 14776 to HY 35459 14194, the now concrete lade (formerly of wood) sits on a solid rubble-built base with the remains of flagstone covering at HY35451 14187. The reinforced concrete lade, which may date from same time as the concrete retaining dam wall, measures 0.36m in depth by 1.02 m in width and 0.87m in internal width. It sits on an earlier rubble base 1.25m in width. From HY 35459 14194 to HY35485 14214, the water was carried to the mill wheel (J) in a wooden, squared-off ‘U’- shaped launder, now gone (4).

WATERWHEEL

The water was taken by lade to a point in the wheel which caused it to ‘pitch back’ or rotate on its axle towards the flow of water from the lade. This is referred to as a backshot wheel (see DC51295). The waterwheel, measuring 4.26m (14 feet) in diameter by 1.21m (4 feet) in width, has (unusually) three cast-iron rings. It had six cast-iron arms and had 48 wooden bucket-floats fitted into the cants in the shroud plates and a square axle. These wooden buckets are all but gone as are the drum boards, but a photograph from 1981 shows them in situ (5).

Little survives of the system operated from inside the mill that controlled the flow of water to the wheel and thus the speed of the machinery. This consisted originally of a wooden lever (extant) to the left of the shelling stones on the first floor of the W range that protrudes through an aperture (measuring 0.4m in width by 0.2m in height) on the N elevation (see DC51291, G). This in turn was attached to a metal rod that was in turn attached to the trap door (opening away from the wheel) in the launder. By moving the lever up and down, the miller could open and close the trapdoor allowing the water to run into the wheel pit without hitting the buckets of the wheel. A sketch map from 1981 suggests that water may have also been released between the two rubble uprights supporting the now-removed wooden launder at HY35484 14214 (6).

W RANGE, MILL BUILDING: Exterior

The W range (water wheel transmission and milling and meal floor area) appears to be the oldest part of the building. Consisting of two floors and an attic, it has six window openings: four on the ground floor (two blocked on SW elevation), two on the first floor (SW and S elevations). There is a double wooden door at ground level of the NE elevation to allow access (see DC51291). The first floor of this range appears to have been heavily re-pointed. The roof may possibly have been replaced at least once as there are non-functioning peg holes visible in the interior at the SW end. This may be evidence of the recycling of timbers from renovated or demolished buildings. The roof is single pitch and is of flagstone. The W elevation has failed and has severe ‘bowing’ in the stonework as a result (DC51291, K).

MILL BUILDING: Interior

Ground Floor

The ground floor (see DC 51290) is paved with flagstone and the walls were been painted white to increase light levels and to cut down on dust and dirt from the milling process lodging in the rough rubble wall surfaces. There are two windows in the W elevation, one in the S and one in the E. The plank entrance doors are locally made with repairs to the lower third. The gear cupboard (A) is intact and is original to the transmission machinery and wheel, although there was probably work carried out at a later date to lower the floor in the gear cupboard in order to insert the shaft belt drive for the elevator and the winnower. A sieve (B) is suspended by leather straps below both chutes from the two sets of stones on the floor above. The bagging area below the sieve (C) has a wooden frame set into the floor with a metal bottom plate and measures 0.73m in length by 0.65 m in breadth. The winnower or fanner appears to be more or less intact (D). The drive for the winnower and the bucket elevator are housed in the gear cupboard at the N end of this range where there is also an access door to the storage area (E); this looks as though it may have originally been a window. The stairway ascending to the first floor is of wood, has ten risers, and appears to be original.

First Floor

The first floor interior is rendered and painted white as on the ground floor, with a wooden floor that had been partially stripped due to wet rot (part of the roof on the N side has collapsed). The roof is a queen-post structure. The original E elevation wall has been punched through to allow access to the first floor of the storage area (where bagging took place from the kiln) and the wall-head and the original roof line shows that the roof structure mirrors the tied wall-line visible on the N elevation (see DC51291, L).

The two millstones for grinding and shelling, with their hoppers, damsels and bucket elevator are intact (see DC 51291). The bruiser has been removed (E). An unusual feature about this mill is the presence of a conveyer belt that carried dried and shelled/winnowed grain from the bucket elevator to the hopper above the grinding stones. The conveyor belt has been removed but the frame survives (F).

STORAGE AREA: Exterior

Moving E to the SE elevation, the storage area was a two floor and attic space with a door, window (ground floor) and two of the three intact partial louvered ventilation windows (first floor). The third louvered window is on the NW elevation (first floor) and there is a glazed window on ground floor. The storage area range butts up against the NW elevation of the W range. There has been some attempt at tying in the masonry. The single pitch roof is of flagstone.

STORAGE AREA: Interior

The interior is rendered and painted white with an original access door on the ground floor. There is an internal doorway to the milling area on the ground floor (see DC51291, L) and the milling area first floor. There is a double door entry to the kiln block at ground floor level. The outline of the removed grain bins can be seen on the first and ground floors (see DC51293, L). These received the dried grain discharged manually from the kiln floor after drying. The first floor wooden flooring has been stripped out due to wet rot, although the joists survive. The glazing survives in most of the windows in this area as do the three louvered windows. The outline of the hoist doors are visible on the first floor and survive on the attic floor (M). This surviving door also has the pulley and rope used to hoist the grain up to the attic and first floors. The attic has a wooden floor with wooden planking standing to 0.69m in height from the edge of the floor to the rafters at right angles, presumably to support grain sacks (N).

KILN: Exterior

The kiln area, which is housed in the E range and roofed in corrugated iron, appears to date from the building of the storage area as the door openings look integral to the build and not to later insertions. There is also evidence of the kiln being heightened. There is a blocked ground floor door in the S elevation that may relate to the 1940s developments (the firebox displays a crude date of ‘1942’ marked in the concrete above the firebox). Alternatively, it may always have been a blind door as it resembles the masonry style throughout this E range of the mill. The only ingress is from the storage area interior. There is a blind window of flagstone on the E elevation that appears to be original and a small window on the N elevation above the kiln floor. The vent has not survived but was of the straight-sided type common in Orkney and Caithness (7).

Interior

The kiln has a central furnace at ground level built of brick. It had a square, funnel-shaped opening into a void through which the heat passed. The heat moved up through the perforated metal floor and through the drying grain spread out on the drying floor above. The missing ventilation vent would have assisted in the drying process. The drying floor is supported by a later steel joist and possibly dates from the furnace rebuild. The firebox area is accessible from the storage area through original, wooden, double doors.

TRANSMISSION AND MILLING

The transmission, which operated the milling process and ancillary processing equipment, is housed in a wooden gear cupboard on the ground floor of the W range or milling area and is fairly typical of watermills generally. This ‘underdrift ‘system where the stones are rotated from below, and most common in watermills, comprises a bevelled pit-wheel (see DC51293, E) attached to the waterwheel axle, which meshed with a wallower, that is at one end of the upright shaft (J). The great spur wheel (F), which is on the same shaft as the wallower, then engaged the stone nuts, which in turn drove the stone-spindles that turned the milling stones (G). The gear wheels are of cast-iron although the great spur wheel has replaceable cog teeth made of wood. The stone nuts were disengaged from the great spur wheel by the ring and screw-engaging gear which allowed work to be carried out on the machinery. Auxiliary equipment was operated from a shaft extending from the gear cupboard (see DC51290, A) with a bevel gear at its E end which in turn engaged with the bevel- pit wheel and two belt drive wheels. These belt drive wheels operated the fanner and the bucket elevator. The sieve below the grinding stones (E set of stones) appears to have been belt operated from above the stone nut of the W pair of stones (shelling stones).

The first floor contains the two sets of stones (see DC51293, A and B), either side of an upright shaft (J). Each unit of the bed and runner stones are within a wooden and iron hooped wooden case or jacket. Above this casing sits a hopper (C) inside a wooden frame or ‘horse’. Dried grain would enter the hopper. The grain flowed into the eye of the runner stone and was controlled by way of a feed trough or ‘shoe’ held in tension by a cord attached to the horse against the revolving cam or ‘damsel’. The ‘cam’ (projection from a shaft delivering pulses of power to a lever) then turned as the stone nut engaged with the great spur wheel below. The grain was forced to the edge and removed by tags that stuck out from the runner stone and into the outlet chute at the base of the wooden jacket. The crown gear is also on this floor (L). This provided the ‘take-off’ power for auxiliary equipment such as the conveyor, bucket elevator and sieving system so that they could be disengaged when not in use.

The sack hoist system is incomplete. There is a block and tackle visible above the hatch on the attic floor of the storage area. There is a wooden frame outline of a hatch on the first floor below although the floor is now missing (M). Unprocessed grain was probably taken from the ground floor up to the kiln access on the storage area attic floor using the block and tackle. After drying in the kiln, the grain was then shovelled via a chute into bins on the first floor. These were accessed from the ground floor via the chute from the kiln foor. From the ground floor, the dried grain may then have been hoisted up through the first floor hatch possibly by means of a windlass (adjacent to the conveyor on the first floor of the W range) which could have been engaged via the crown gear wheel to operate the hoist in the storage area. The grain could then be moved to the milling floor of the main mill building (W range) for milling. There was no evidence of hatch doors in the milling floor (1st floor, W range), although the floor is incomplete due to wet rot.

MILLING

The process of milling bere meal and oat meal can be seen through the plans and sections (DC). Grain would be emptied (manually) into the hopper above the shelling stones (westernmost stones) on main mill first floor, thence to the winnowing machine/fanner on the ground floor. The removed chaff was stored at on the ground floor behind the winnower and used as fuel for the grain drying process. The cleaned grain or groats were sent via the bucket elevator to the first floor milling area. The elevator emptied onto the overhead conveyor which carried the grain to the uppermost of two hoppers above the grinding stones and thence to the sieving machine on the ground floor and bagged up. Grain destined for animal feed would be dealt with in a slightly different way, as the dried grain would be passed through a bruiser (now gone), but visible in a photograph from 1981 (8) and probably bagged up below on the ground or meal floor.

Glossary

BED STONE: lower and fixed or ‘bedded in’ stone of a pair of millstones

BERE MEAL: meal from an old form of barley which is still grown in northern Scotland and Scandanavia

BEVELLED PIT GEAR: gear with the gear teeth set at an angle which its on the shaft on which the waterwheel and the pit wheel turn, also known as the axle tree

BRUISER: for animal feed preparation

BUCKET ELEVATOR: equipment for moving winnowed grain between winnowing machine and grain hoppers above the grinding stones in a grain mill

CAM: see DAMSEL

CANTS: part of a waterwheel into which the mortise is cut to take the wooden bucket floats

CHAFF: debris removed from grain in a winnower

CROWN GEAR: wheel with teeth on upper surface that sits at the top of the main shaft and runs auxiliary machinery

BUCKET FLOATS: enclosed floats around the edge of a waterwheel that receive water from the launder

DAMSEL: metal extension of the spindle which turns circular motion to horizontal motion by jolting the shoe and maintaining the flow of grain from the hopper to the mill stones. This is technically known as a CAM or a feeder.

DRUM BOARDS: lining boards in metal or wood that ensure water does not escape from the buckets on the waterwheel

FANNER: see WINNOWER

FLASGTONES

GEAR CUPBOARD

GREAT SPUR WHEEL: gear wheel which engages with one or more stone nuts in a grain mill

GROATS: grain that has been cleaned

LADE: mill race; conduit carrying water to a waterwheel and onto the natural source

LAUNDER: an open channel of wood or concrete carrying water onto a waterwheel, extension of the lade; also know an as pentrough

QUEEN-POST ROOFSTRUCTURE: horizontal tie beam carrying two vertical posts (queen posts) in turn supporting a horizontal beam or collar tied to the main rafters and purlins of a roof

RUNNER STONE: upper and rotating stone of a pair of milling stones

SACK HOIST: the means by which sacks of grain are moved vertically between floors of a grain mill, usually rope or chain and windlass operated mechanically from crown gear

SHELLING STONES: stones which break the shells of grain before sending to winnower and prior to grinding in grinding stones

SHROUD PLATES: the two rim plates which protect the edge of the waterwheel

SLUICE GATE: gate for controlling water intake to a lade

STONE NUTS: pinions on the stone spindle which engage with the spur wheel

TAIL RACE: lade or mill race beyond the waterwheel as it returns to the natural source

UNDERDRIFT: mill stones operated from below

WALLOWER: a small toothed gear on the main upright shaft in gear with the pit wheel

WINNOWER: machine for removing chaff from grain by means of a current of air

(1) By 1854, the mill was owned by Robert Scarth (one third), William Clouston and William Isbister owning the other two thirds jointly (Valuation Rolls for the County of Orkney, 1854-1855, Kirkwall, parish of Firth, Folio 51, item 40 and 53, Orkney Archive Ref CO4/3/MF1). Scarth took out a 38 year lease on the whole mill around 1857 and was involved in it until his death when his son apparently took it over (Valuation Rolls for the County of Orkney, 1906-1907, Kirkwall, parish of Firth, item 46). Milling ceased in 1955 when in the ownership of the last miller, William A Paterson.

(2) RCAHMS MS/500/35/22, sheet 1, 22/10/1981

(3) Ordnance Survey first and second editions of the 6-inch map, 1882 and 1902 (Orkney and Shetland, sheet CI).

(4) RCAHMS MS/500/35/22, 22/10/1981, RCAHMS B26208/PO

(5) RCAHMS MS/500/35/22, 22/10/1981, B26208/PO

(6) RCAHMS MS/500/35/22, sheet1

(7) MS 500/35/22, B26207/PO; Shaw, J 1982 ‘Introduction to meal milling in Scotland’, Scottish Industrial History 51, 18; 19th century photograph, Kirkwall Library Ref: 1405.

(8) MS/500/35/22, 22/10/1981, RCAHMS B15077

Visited by RCAHMS (MMD) 3 - 7 November 2007.