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Technical descriptions of English windmills


ORSETT, Baker Street

Smock mill, standing today


Baker Street smock mill probably dates from c1796. It bears evidence of major structural alteration, but most of the machinery appears to be original.

 The eight-sided brick base, rendered outside with cement, and having vertical whitewashed walls inside, is nearly 3ft thick at ground level. It has east and west facing doors, a third entry door on the north side, where the steam mill was built on, and it rises 17ft 8in, at which level the brickwork is about 18in thick. There is a slight batter, and the distance across the flats inside at ground level is 20ft 4in. The aperture for the north door had evidently been made by removing the brickwork beneath a former window. The oak sills, about 8ft 6in long by 10in wide by 6in thick, are dogged together on their outsides, where they carry sprockets, and the dogs are secured on their inside by cotter bolts. The sills have chiselled numbers for assembly, each sill having the same number at each end inside, and additionally outside at the junction with the intermediate vertical.

 The cant posts are in pine, shaped from timber 9-10in sq, and extend for about 21ft from sills to curb. The curb is of about 11ft internal diameter, is 10in across by 12in deep, and in two rings 4in deep above and 8in below. The eight lower segments are united over the intermediate uprights by remarkably complex joints involving eight right angles along the matching edges and a central wedge for tightening. The curb rings are dowelled together, and carry a 4in iron skid track on top. The cant posts enter the curb and sills with vertical tenons, and at curb level are on 50in centres measured as chords of a circle.

 Between curb and sills there are two sets of transoms 7in sq or less in section at approximately 4ft and 11ft centres, respectively, below the curb centre, and these are tenoned into 2in wide mortises in the cant posts and are applied also to housings on the outsides of the posts. In the two lower of the three panels so formed on each face of the smock frame are set an intermediate vertical, 2 diagonals and 2 studs; in the uppermost panel there is an intermediate vertical only. The frame is covered by horizontal 1in boards of pine with ship-lap abutment for much of its height, over which normal weatherboarding is laid, but the highest 7 or 8 weatherboards tend to a 16-side under the curb, and are butted over the intermediate verticals directly. The diagonals above mentioned are footed in the angles between sills or transoms, as the case may be, and the cant posts, and are notched slightly into the intermediates.

 It is when we come to examine the relationship of floors to transoms, the construction of the floors, and other details that evidence of change becomes insistent. As in the case of Wicken Bonhunt mill, the smock frame appears disproportionately short and inwards-canted for its present base, which consists of yellow bricks below and bright red bricks in the upper part, leading to the conjecture that the wooden frame of the mill was jacked up and the base heightened. Possibly at that time the stage was added; it lay 8ft 6in over ground level, was about 7ft wide, and was supported by oak struts from the brickwork springing from 3ft above the ground. The struts were bolted through the brickwork. A curious feature on the north-west side was the building of an outhouse directly around one of the stage supports. Loading doors were provided on the south-west and north-east sides of the first floor, and elsewhere were good windows.

 The mill floors, in descending order, and with heights from curb base to dust floor and then from floor to floor below, as checked in 1967, were: dust 3ft 10in; bin 6ft 9in; stone 8ft 7in; spout 9ft 10in; ground 9ft 6in. Beneath these floors the main beams, all of pine, ran alternately east-west, beginning with the dust floor, and north-south (bin and spout floors), and the two lowest floors were within the brick base. The first or spout floor beams, also on 6ft 9in centres, were built into the brickwork, and were coupled across by a pair of similar section beams, also on 6ft 9in centres, to form in plan an H with a double bar. These transverse timbers were supported at centre from below by 2 vertical stanchion posts 9in sq with single flat wedges driven in recesses at their tops to ensure a full and effective support. The second or stone-floor beams above, of similar size and spacing, ran east-west to rest directly on the sills inside two pairs of cant posts to which they were single-bolted, and these beams were supported by stanchions at centre directly over the pair beneath them. Both floors had joists 7in by 2½ in on 14-15 in centres carried almost wholly above them and set with the longer dimension vertically in the modern manner, suggesting a replacement of the original fittings. The stone-floor joists terminated somewhat awkwardly above the sills, over which blocks were spiked as supports.

 The ends of the north-south aligned bin-floor beams, 8in wide by 13in deep, were inside the cant posts and below the lower set of transoms, being held by a single 1in diameter bolt in each case put through beam and cant post horizontally, and supported from below by a large tapered wood bracket spiked to the inside face of the cant post. The floor beams rested intermediately on four vertical pine members halved up against their inside faces. The pine posts bore a close resemblance to telegraph poles, and they were spaced 4ft 9in on centres east-west and 6ft 9in north-south. Like the two posts below they were put to several uses additional to propping, as described later.

 The east-west dust floor beams, about 8in in diameter and resembling the poles used below, were also bolted to the cant posts, bracketed beneath and – again contrary to normal practice, fixed underneath the transoms. It is thanks to the conjunction of floor beams and supporting posts extending from ground to bin-floor levels that the smock frame has not long since collapsed, for the cant posts have largely ceased to bear more than a small fraction of the load.

 It would seem likely that all the floors were replaced after the mill had been active for many years, using the rounded pine timbers for the dust-floor beams and dressed pine beams for the first two, while the bin floor pair had various cuts and mortices indicating previous use, perhaps in this mill. Whether these changes were consequent upon raising the brick base is uncertain. Empty mortices in the cant posts, which might have provided clues to former floor levels, unless the posts too were changed, were not recorded in the notes, which makes it unlikely they were present. The mill probably began life with dust, bin, stone and ground floors, with the stones discharging into sacks at ground level. Adding a floor on the brick base would have given more room for machines and storage and easy loading onto carts from a stage, the stones then discharging to the first floor.

 The cap was wagon-shaped, with blisters for the brake wheel, and must have risen to about 8ft over curb level, giving the mill an overall height of some 46½ feet. The cap spars were open-morticed and tenoned, having no ridge piece. The sheers were slight, at about 8in sq in section, and were tied by irons fore and aft of the brakewheel, there being a notable lack of good cross members. The tailbeam had been moving backwards in later years, and was well tied, therefore, to the spindle beam. The fantail staging pieces were bolted under the spindle beam and the 8-bladed fantail was carried on two long inclined arms supported by cross-braced members below, the whole clearly an addition to the formerly hand-winded cap. Hand winding, if required, was still available by chain operation from a Y-wheel with 16 Y-pieces on the left rear of the cap, operating through reduction gearing the heavy “wooden-type” iron worm on an iron shaft. The worm was mounted on 2 pendant timbers of heavy section tied across below the worm with an iron rod, and the worm gear drove against 64 wooden cogs of about 6¼ pitch around the curb. To the right rear was a further Y-wheel to operate the striking gear by pinion over a rack, and the chain for this formerly passed to the stage below over two guide pulleys in a horizontally projecting timber hung from two vertical pieces.

 The cap ran on two rollers under the oak weatherbeam, but under the sheers and elsewhere had skid plates. It was centred by two large curved elm rubbing blocks on either side of the cap frame bolted up to the sheers, and each extending for about 1½ times the distance between neighbouring cant posts; there were also two centring wheels below the tail beam at the rear, but no provision at all in the front. Under the tail beam was another rubbing piece, probably original, later supplemented by the wheels placed on either side. The wood bearing pieces were shod with iron, but ran against the wooden face of the curb ring, 4in wide, above the cog tails, and the side rubbing pieces were iron-bracketed to the spindle beam and sheers, reinforcing the whole assembly.

 The iron windshaft was an interesting casting. Immediately behind the plain canister were cast two flanges about 1ft apart, between which were inserted alternately some 36 iron and wooden strips secured by two semi-circular hoops at either end bolted together. There was a plain bearing, probably of brass, in the iron bearing box below. The purpose of this neck-journal design, seen also at South Ockendon and, formerly, at Upminster mill, was presumably to retain the grease by virtue of the wood included. The renewal of strips would have been comparatively simple. Between the neck bearing and the brakewheel, the shaft changed from hexagonal to square in section by a well-contrived exercise in solid geometry involving edges progressively flattened rearwards, but was not fully noted; the square section was for the brakewheel, for which no cast-on box was provided, but a separate iron unit was wedged on to accept the wooden wedging from the clasp arms of the brake wheel. The windshaft tapered at rear in the form of a 12-side about 5in across the flat, beyond which the journal was enclosed in a glut or grease box in two halves, bolted together over and under, providing also a “keep” against a rise of the tail. One may presume this to have been a custom-built shaft designed for the replacement at this mill of a wooden shaft carrying the built-in compass-arm brakewheel before its conversion to clasp-arm. This wheel, about 8ft diameter, had four elm cants with weak overlaps, necessarily strengthened by wooden triangle pieces edged into the four corners of the frame. The cogs, of just over 3in pitch, were unusually thin, having no shoulders for abutment to the felloes, and they meshed with large square-cut cogs on the wallower, the two sets being apparently made with the maximum economy in labour, probably by a hard-pressed miller who could not afford a millwright’s expenses.

 The wooden upright shaft was in one piece of oak about 14ft long, and was 12in square at the wallower and 14in octagonal below across the flats (18in 12-sided at the great spur mounting). It was footed on an elm sprattle set about 4ft 6in on centre over stone-floor level, the stones being overdriven. The sprattle was 8ft 4in overall by 12in wide by 10in deep at centre and shouldered on two supports, also elm, and 5ft 6in long overall, with single tenons at the ends which were let into elongated vertical mortices in the 4 D-section pine posts described above. The sprattle was adjustable at its ends for north-south movement, viz. in line with it, and its bearers were adjustable at their ends for movement at right angles, all adjustments being by two-way tapered or self-retaining wedges, but coarse cloth was also used at the sprattle ends. There was no screw adjustment at the foot of the u/s. The top spigot of the shaft ran in an all-wood, two-piece bearing on the underside of the spindle beam. The shaft was squared for almost two feet below the wallower, suggesting a change of setting at one time, but the wallower could have been the original, consisting of two solid-planked discs each 4½ in thick, bolted together through flat iron rings above and below, and bevelled upwards at the circumference from 44in to 38in diameter, with about 44 cogs inserted. On the bin floor was a wooden down-turned face gear of 44in diameter overall, driving via a long slack-belt control system to a lineshaft on the first floor. Fig.11d illustrates the machinery as if distributed in one vertical plane.

 The 7ft great spur gear was a fine example of a compass-arm wheel, having 6 visible arms 8½ in deep by 3½ in wide at their point of entry into the shaft; one pair, formed by a single timber passing through, was straight, and the others curved, one up, one down from the wheel rim for staggered entry into the shaft. The whole was assembled with wedges in a manner similar to that described for Tiptree mill. The six cants were 13in wide at centre and 3½ in thick. They were united into a ring with follow-round tenons and held firm by sunk and curved butt-straps over and under, bolted through. The rim of the wheel was completed by 7in wide by 3½ in thick felloes, breaking joint with the cants, and carried 109 cogs of 4½ in face and 2½ in pitch, with shanks held by modern wire nails.

 There were three pairs of overdriven 4ft stones: west, east, and an added pair on the south. All the stone nuts were the 4-armed iron mortice type, 18½ in diameter overall, with 22 wood cogs of 5in face and with dovetailed shanks for wedge-fixing at the rear, the wedges being driven between adjacent shanks. The west and south stone nuts had square bosses on square quants and the east on round boss on a round quant, and all had an iron collar or clamp on the quant just below the nut to retain the wedges fixing nut to shaft. The square quants and a square on the circular quant served to vibrate the shoes for grain feed. All three quants were disengaged from glut boxes in beams wedge-adjusted at both ends, where they derived support from various timbers and chocks attached to the bin-floor beams or the smock framing.

 The bell-alarm system could have been the longest to survive in any derelict windmill in the country, thanks to its obscure location. It was only discovered by Denis Sanders in the course of his fifth visit, in October 1967. He stood on the east stone case and thrust head and shoulders through the arms of the great spur gear to find nestling in the joists above “an absolute peach – a cluster of bell alarms!” These consisted of three pendant timbers 1ft by 3in by 1in with the bells at top and suitably pivoted in a row between two inverted wooden trunnions attached to the underside of the bin-floor joists. When the hoppers held grain the pendants were turned up by cords in tension passing over small pulleys above, and were therefore clear of the passage of vertical finger pieces fixed to the leading side of the straight arm on the great spur gear. If a hopper ran dry, the corresponding pendant timber swung down and was struck on each rotation of the great spur gear, thus alerting the miller. The cords had gone by 1967, though the stone cases and horses remained; the east and west cases were round, the south octagonal.

 For stone raising, eye bolts were let into timbers bolted up to two or three joists for the older stone positions; the method for the south pair was not noted. The stone bearers for the older stones were set across the east-west floor beams on about 30in centres and consisted mainly of re-used and very rough timbers. The difficulties of assign a third pair of stones were well illustrated in this mill. The south stone bearers were set north to south from the south main floor beam to large blocking timbers laid over the smock sill on the south face, recalling a similar arrangement at South Ockendon mill. The bedstone rested over these two bearers and also over the floor beam and one transverse member. The octagonal stone case was trimmed to the two storey posts adjacent, which helped to block off the meal, and the hopper above was specially shaped to avoid a post. The quant required a minor clearance cut in the sprattle end and its support. Below the stone floor a 3in chase for the stone spindle was cut in the south face of the south floor beam, and to allow clearance for the bridgetree a cut 5in deep and over 1ft in length was taken out of the 9in sq section of the south spout-floor storey post. To compensate, a backing piece 43in by 9in by 5in was added to the post. A cut was also needed for a section of the two-stage belt drive from the stone spindle to the governor, which controlled the west end of the bridgetree directly, the use of a bray being dispensed with.

 All three bridgetrees were set tangentially to the spur gear (on the floor above), and so ran north-south in the case of the west and east stones, which had their brays respectively at the north and south ends, this being a common arrangement to avoid bunching. The brays and bridgetrees were wood to wood at the coupling, with a rounded bed on the bray for the end of the bridgetree to rest in. The hangers supporting all this gear, fixed to the stone floor beams, showed evidence of modification and change of position. Dovetailed housings were used at the meeting faces of the halved hangers and beams. The governor-controlled ends of the brays for the west and east stones were carried by chocks on the north and south storey posts, and the three two-ball governors, each belt-driven from a stone spindle, were set in frames situated as illustrated in the plan.

 The west bray, which was 5-6ft long, effectively, between its supports, had the semicircular bed for bridgetree support, but had for some reason been inverted, and an older arrangement for carrying the bridge was there preserved on the underside. This was a thin piece of timber 2in wide by 14in long, slightly dished at centre, let into a longitudinal mortise in the bray and brought to the required position by wedges at each end. The mortices for the wedges ran right through the bray and were about 5in long by 1in wide. This device was noted also at Little Saling.

 The sack-hoist bollard was set between a framing built up on the dust floor beneath the wallower – of which the hoist was independent – and the north-east face of the mill, and from it the sack chain was taken to a pulley on the intermediate member below the curb at this point, and so down the traps on the north side of the mill. A wooden compass-arm pulley, being an old wooden spur gear in two planked halves with cogs sawn off, and placed on the inner end of the bollard, was raised to take the drive by slack belt from below. The belt was driven from a wooden flanged pulley on a shaft with a wood spur gear operated by the downturned face gear of about 44in diameter on the upright shaft, mentioned earlier. The driving spindle and its wheels was suspended 15in below the dust floor, and one of the main floor beams in the path of the belt was cut deeply, but given added support by a post footed among the bins. An older sack hoist position over the traps was noted.

 On the south side of the bin floor was a second spur gear, solid wood-planked, also driven from the gear on the upright shaft on this level. On the same wooden octagonal shaft was an all-wooden clasp-arm pulley set as close to the mill frame as possible to be over its driven pulley on the spout floor below. The drive from above was to a 4ft octagonal wooden-line shaft with 3 pulleys, which was slack-belt controlled in the opposite sense to the usual. One end of the line-shaft, towards the mill centre, was held in a vertical timber which could be raised and lowered in guide mortises in two horizontal chocks on 2ft centres attached to the west hanger of the south bridgetree. When the rope fall from the lever was pulled and fixed, the belt was slack; when it was released the drive was communicated from above. The drive came to a 2ft diameter 6½ in wide face wood pulley, and hard against this was a 3ft diameter 5½ in wood pulley for dresser drive on the east side of the spout floor. The larger pulley gave 5ft 10in headroom when driving. The bolter close to the ceiling of the spout floor was driven at the upper (south) end, where was a wood pulley with a single flange, the end of a tortuous route from just beneath the dust floor! At some stage in its history, the mill carried a dresser on the stone floor. A thin pulley on the lineshaft drove a small pulley in the south-east quarter with a crank on the spindle, which actuated a vertical rod passing down through guides close to the wall and through the first floor, and so to a rope with a horizontal bell crank on the end to work a sack jigger close to the discharge from the flour dresser.

 With all this machinery and equipment crowded into such a confined space, it may well be asked whether the miller was left much freedom to circulate. The answer is very little above the spout floor; nevertheless the machinery was left unguarded contrary to the precautions at South Ockendon, but there the concern was not for the miller’s safety. The floor heights are of interest in relation to the miller’s freedom of movement, headroom being allowed where possible beneath suspended fittings such as bridgetrees, gears and pulleys. The consumption of space by sack traps, ladder wells and filled sacks was considerable.

 The steam engine drove two pairs of stones underdrift, but was independent of the windmill. A distance of some 15ft separated the windmill base from the steam mill building, though the two were connected by a walled and roofed passage. Notes on the steam mill were taken, but are excluded here.

 The last sails, both clamped over the sides of the canister, were anti-clockwise double-shuttered patents. The outer pair had 8 bays of 4 shutters and an inner bay of 3, while the inner pair had 11 bays of 3, making totals of 35 and 33 shutters respectively. Leading shutters measured 27in by 9in and were made of 3/8 in stiffeners clench-nailed on, and the pivots for their cranks were on approximately 5in centres. A driving shutter inside the mill measured 37in by 9in. On the surviving outer sail in 1967 it was noted that the inserted thimbles for the leading shutters were set in the whip direct, but that the driving shutters had the cast pivots on a wood bar running up the side of the whip. The spider was arranged in swastika fashion, with short links to the triangle on the forward middlings. These sails passed close to the staging.

Vol 4: On the stone floor, which lies over the brick base, two inscriptions were noted, one above the other: R B 1814 (carved) and S S 1762 (painted). They are at 5½ feet and 20in over floor level, respectively. Both are on the inside face of the wide rabbeted pine boarding and by their curiously disparate heights suggest a body-raising operation between the dates given, assuming the earlier dated timber was not imported ready-marked from elsewhere.

 The octagon of the smock frame is slightly askew from that of the brick base, which may indicate the lowering of a jacked-up frame on a heightened base. Despite the fact that the two upper sets of floor beams relate awkwardly to the transoms, there is no evidence of floor-level changes within the smock by way of vacated mortices or notches in the cant posts.