the Mill; they are the reason all
this machinery exist, to enable
the Stones to grind the corn.
DESCRIPTION
The stones are arranged in pairs;
the upper ‘runner stone’ rotates
above the lower fixed ‘bed
stone’ or ‘Ligger’. Sizes varied
over the years but a diameter of
4 feet came to be accepted
generally as most satisfactory.
Each stone weighed over a ton
when new.
The best having been imported
from continental quarries, in the
Rhine Valley for instance, since
the Roman occupation of Britain
well into the Middle Ages. But
due to their enormous weight
and transport being slow and
costly, millers were forced to use
locally available stone. Here in
Britain this was millstone grit, a
hard sandstone from Derbyshire’s
Peak District and known as ‘Peak
Stone’ other less satisfactory
stone like West Midland
sandstone and Welsh or
Dartmoor granite.
More recent imports were
‘Dutch blue and ’Cullin’ stones
named after Cologne.
Most highly prized of them all
were ‘French burns’ skillfully
pieced together from small
blocks of quartz, quarried near
Paris. The pieces were matched
together and set in cement and
bound with iron hoops then
backed with plaster of Paris. They
are identifiable by their
patchwork appearances.
rotation for the runner stone is
about 125 revs. per minute and
required at least 10 horsepower
to drive one stone. Sources of
material suitable for these stones
were few and far between, so
good quality millstones were
very valuable indeed.
prepared carefully by skilled
stonedressers, craftsmen in their
own right, the first essential
being a smooth surface slightly
dished towards the ‘eye’ in the
centre. Then a system of ‘furrows’
which do the actual grinding,
were set out in traditional
patterns built on experience
established through years of trial
and error to suit the particular
use to which the stone was to be
put. Common dressing, consisting
of ten equal ‘harps’ or sectors laid
out tangentially to the ‘eye’
subdivided into alternate ‘lands’
and ‘furrows’ half to three
quarters deep, sloping gently up
to the land on one side and
dropping sharply on the other.
Finally the dressing was
completed with a system of fine
parallel grooves, the ‘stitching’ or
‘cracking’ 1/16th apart. When the
stones are in their working
position, face to face, the ‘furrows’
cross at each revolution cutting
the grain with a scissor action. As
the stones become dulled with
wear they had to be redressed by
the stonedresser who deepened
the ‘furrows’ and renewed the
stitching. In a busy mill like Marsh
Mill this was about every month.
placed in positions, the bearings
of the spindle on which it was to
turn were carefully adjusted to
allow the stone to rotate in a
perfectly horizontal plane. This
task was called ‘brigging the
spindle’ and was facilitated by the
iron ‘bridging box’, a square iron
container housing the thrust
bearing, the position of which
can be altered in two right-
angled planes by means of
projecting hackle screws.
the grinding surfaces of the
stones required extremely subtle
adjustment on order to produce
the desired texture of meal, taking
inot account both the hardness of
the grain and the speed of the
Mill which still varied, despite
automatic ‘Reefing’ with wind
pressure. This fine adjustment was
called ‘tentering’ and was effected
by raising or lowering the ends of
the stout timber beams, or bridge
trees, which carried the stones
spindles.
