Windmill

History

The Lower Mill Dalham is a large, octagonal smock mill, and was originally built in the 1790’s, we suspect for a Mr.Ruffle (or Ruffell). The first clear reference to the mill is a mention of it being damaged in a storm in the December 1802 issue of the Ipswich Journal, when the sails blew off.

The mill was very active during the 19th. Century with a number of millers mentioned in the Suffolk Trade Directories. The last miller was a Mr Turner of Street Farm, who ran the mill until 1926. The Lower Mill, or the ‘Opposition Mill’ as it is known locally, was mainly used by the Dalham Hall Estate, who owned it for a number of years until it was sold to Mr. Farrow (the present owner’s grandfather) in 1969.

There are two rival origins for this name Opposition Mill: i. Having been built after the Ashley mill (the remains of which can be seen a 1/4 mile above it at TL716617 – it was declared unsafe and was burnt down in 1964), inevitably the Dalham mill took some of the Ashley mill’s trade away. It has also been suggested that the Dalham mill was built by the Upper Mill’s younger brother in opposition to his brother. ii. Or it is alleged the Dalham mill’s sails turned in the opposite direction to that of the Upper Mill.
Structure

From the ground to the top of the ball and stalk finial on the ‘Beehive’ cap, the mill is 50 foot high. The eight-sided wooden tower is mounted on a circular brick base, with minimal foundations, based on a chalk outlier. It is extremely well sited – even on a still day in the summer this position is windy.

a. Sails

The mill had four 27 foot long, 7 foot wide ‘Patent’ sails (although it was probably constructed with canvas covered ‘common’ sails). These sails were constructed from pitch pine and were double-sided; each side having 9 bays of three shutters, giving a total of 54 hinged wooden shutters per sail. By opening these shutters (i.e. edge to the wind, or making them broad to the wind, or closing the shutters altogether) the speed of the sails could be controlled, even when they were turning. This operation was controlled via chains hanging on the exterior of the mill, down to the ground – surprisingly this form of control is exactly the same as that used to adjust the rotor blades of a modern helicopter! The main centre timber of the sail was known as the whip. Each whip was fixed to a piece of heavy timber called a stock. The two stocks (some 12′ square, then tapering to 7′ and several feet long) in turn passed through the two square sectioned shaft bosses at the end of the cast iron wind shaft. Two sails were attached to each stock. At the rear of the cap, precisely 180 degrees behind the main sails, was a fantail which was used to aim the sails into the wind – this was removed in 1934. This much smaller sail was geared into the cogs in the cap’s curb. As the wind changed direction, so it impinged more on one side of the fantail than the other, turning the entire cap (to which it is attached) until such time that the pressure is equalled – at that point the sails were then full into the wind.
b. Operation

As the schematic illustrates the mill has five floors and the process of grinding the corn was an essentially simple sequence.

(1) Sacks of grain were taken in on the ground floor ‘Reception’.

(2) From there the sacks were lifted by a wind-powered hoist to the second, or Bin Floor, where it was stored in separate bins for each farm.

(3) From these bins the grain was poured into a hopper that fed one of the three mill stones on the Stone Floor below.

(4) As the grain was ground, so it gravitated to the outer edge of the stone, was trapped by a tun and flowed, via a spout, into sacks. As the wind’s speed varied the weights of the centrifugal governors rose or fell, operating a breyer lever which in turn raised or lowered the bridge tree, thereby controlling the gap between the runner stones’, e.g. a rise in the governors’ steelyard of 6″ translated into an increase of 1/64th” in the gap between the stones, thus finely controlling the flour’s quality. Finally,

(5) the sacks of flour were winched onto waiting carts below one of the two loading doors on the first floor.

c. Key floor details

i. The cap

a. On the exterior of the cap is a gallery that was used for maintenance.

b. The cap is built on a horizontal frame of wood and between it and the tower is a rare shot curb roller bearing – you need to climb the ladder to demonstrate this. Note that the curb, cap ring and rim of the brake were constructed from elm, while the cogs were made from extremely hardy apple wood.

c. The brake wheel is incomplete, with only the two brake ‘shoes’ in place. The brake was operated by a large lever and was used to knock out the power in high winds or at night

d. Within the cap, the power of the sails is transferred to the vertical main shaft drive from the cast iron windshaft via a vertical crown wheel (which is in the pile of ironwork on the floor) thence to a horizontal one.

e. Over your head there was a Dust Floor, now missing, which acted as a partition to keep dust out of the cap and the sack hoist and eased access to the exterior gallery.

f. The sack hoist could be operated manually, or wind-driven using the belt drive located on the floor below.

g. The pile of ironwork in the corner largely consists of the remains of the sail shutter mechanisms and parts of the brake shoe (wooden pieces of which are also to be found on the floor below)

ii. The bin floor

a. Below the Dust floor is the Bin Floor. While the sacks of grain were taken in on the ground floor, the ‘Reception’, they were then lifted by a wind-powered hoist to the second, or Bin Floor (if this was full then the Dust floor would also be used for grain storage), where it was stored in sacks.

b. As grinding commenced it was transferred to separate bins for each farm / customer. From these bins the grain was poured into a hopper that fed one of the three millstones on the Stone Floor below.

c. On this floor is another balanced crown drive, which could be driven by the auxiliary drive – most recently this was a steam drive, located outside the mill cottage which, via a belt drive, turned the drive wheel on the outside of the mill, below the wind shaft.

d. In one corner are various pieces of wood debris – this is the remnants of the brake and sections of the old cap curb – note the wear on the apple cogs.

iii. The stone floor

a. Below this is the Stone Floor, dominated by the very unusual Hurst Frame, reputed to be the only one in the country. This massive wooden table supports three sets of 4 foot + diameter millstones made from Buhr (quartzite quarried in France, hence the term ‘French stones’).

b. The grain arrived at the centre of the stone via a sacking tube on the bin floor. From the receiving hopper its flow was controlled down a shoe into the centre of a stone.

c. As the grain was ground, so it gravitated to the outer edge of the stone, was trapped by a tun and flowed, via a spout, into sacks by the side of the stone.

d. As the wind’s speed varied, so the weights of the centrifugal governors rose or fell. This movement operated a breyer lever which, in turn, raised or lowered the bridge tree, which controlled the gap between the runner stones’. A rise in the governors’ steelyard of 6” translated into an increase of 1/64th of an inch in the gap between the stones. By this means the flour’s quality could be finely controlled.

e. Note that there are only two stone hoists left.

f. Also note there is a bill for dressing the stones and a stone level.

g. Finally, the sacks of flour were winched onto waiting carts below one of the two loading doors on the first floor.

h. There could have been a fourth set of stones on this floor.