The Story Behind the Picture

   When   the   tower   rebuild   was   finally   completed   we   knew   the   next task   was   to   find   and   fit   a   curb.   This   was   a   job   only   a   professional     millwright   could   undertake   and   it   was   frustrating   that   despite        asking   our   contacts   for   several   months   about   the   chances   of getting   hold   of   a   second-hand   one   or   failing   that   what   the   price for a new one would be we could never get a definite answer.    Then,   finally,   a   breakthrough   occurred   and   the   situation   changed dramatically   for   the   better.   We   were   driving   past   Mount   Pleasant Mill   in   Kirton   Lindsey   and   we   noticed   it's   cap   had   been   removed and   was   sitting   on   blocks   in   the   car   park.   On   enquiry   the   owner told   us   that   following   'back   winding'   the   iron   cross   had   snapped causing   serious   damage   and   that   the   repairs   were   being   carried out    by    Adam    Marriott    from    Teme    Valley    Heritage    Engineers. Wasting   no   time   we   contacted   Adam   and   he   promised   to   come over   and   see   our   project   as   soon   as   he   had   some   free   time.   A site    visit    eventually    followed.    After    climbing    the    tower    he commented   favourably   on   the   dimensional   accuracy   of   the   new

brickwork   we   had   commissioned,   declared   the   job   feasible   and promised   to   quote   us   for   making   and   fitting   a   brand   new   tailor- made   curb.   To   cut   a   long   story   short   we   accepted   his   quote   and work   started   on   the   tower.   First   we   removed   the   waterproof cover   which   allowed   him   access   so   he   could   take   a   pattern   in plywood   of   the   top   the   brickwork,   marking   the   exact   position   of the   built-in   holes   for   the   holding   down   bolts.   Taking   this   back   to his   workshop   he   recreated   the   total   circumference   of   the   tower and   divided   it   into   eight   identical   segments   thereby   establishing their   dimensions   in   plan   view.   After   considering   several   options he   chose   the   mechanical   design   he   thought   most   suitable   for   the completed    curb.    This    was    passed    to    a    patternmaker    whose finished   work   can   be   seen   in   fig.1   painted   red   together   with   a nine   toothed   pinion   in   yellow   to   gear   down   the   fan   speed   and provide   sufficient   power   to   drive   the   cap   round.   Adam’s   extensive knowledge   of   metallurgy   was   employed   in   selecting   a   grade   of cast iron which is far stronger than the original.

Artist’s Impression of the Mill after Restoration

Fig.1

Fig.2

Fig.3

Fig.4

This   can   be   seen   in   fig.2   being   poured   into   the   mould   at   the foundry, Purbright & Co Providence Works, Willenhall.    There   were   a   few   problems   with   the   pours   but   eventually   we had   a   full   set   of   curb   sections   (fig.3)   ready   for   fettling   and transporting back to his works at Teme Valley.    While   casting   was   in   progress   Adam   contacted   his   timber suppliers   and   made   a   selection   of   restoration   grade   oak.   This was   cut   into   a   set   of   eight   curved   segments   complete   with     mortise   and   tenon   joints   in   each   of   their   ends   so   they   could be   assembled   into   a   complete   circle   to   fit   the   brickwork   top (fig.4).   Lying   on   them   is   a   section   of   the   plywood   pattern Adam   had   taken   at   the   mill.   Now,   with   all   the   parts   to   hand, he   made   a   trial   fitting   in   his   yard   where   he   checked   the relevant   fits   and   when   satisfied   all   was   good   drove   to   the   site in Filey

and   assembled   the   complete   curb   unit.   First   the   oak   frames had    to    be    joined    using    a    rubber    mallet    to    ‘persuade’    the mortise   joints   to   align   (fig.5).   When   satisfied   the   circle   was true    the    joints    were    pegged    with    trenails    (fig.6)    and    their excess   length   was   trimmed   off   with   a   saw.   The   cast   iron   curb

sections    were    then    man-handled    onto    the    frame,    slid    into position,   and   fastened   down   securely   (figs.7   &   8).   We   now   had   a fully   operational   curb   sitting   on   straw   bales   waiting   to   be   craned up   the   tower   and   bolted   into   position.   We   couldn’t   thank   Adam enough after our earlier frustrating experiences.

By   now   it   was   the   end   of   October   and   our   problem   then   was when   to   book   the   hire   of   the   crane?   The   weather   parameters were   a   dry   day   with   a   wind   speed   of   less   than   10mph.   We studied    the    medium-term    forecast,    found    a    date    with    what should   be   acceptable   weather   and   that   suited   all   the   parties involved crossing our fingers it would turn out as forecast.    The   day   arrived   and   conditions   could   hardly   have   been   any better.   First   a   working   party   set   to   work   removing   the   heavy plastic   waterproof   cover   from   the   tower   using   a   cherry-picker.

By   the   time   they   had   finished   the   heavy   crane   had   arrived   on site.   Adam   liaising   with   the   banksman   and   crane   driver   soon had   the   curb   assembly   lifted   off   the   bales   and   raised   above   the mill   (fig.9).   Because   of   its   weight   the   positioning   had   to   be precise   in   order   for   the   holding-down   bolts   to   align   with   the tubes   built   into   the   brickwork   leading   down   to   the   oak   pads. Adam   had   marked   on   the   timber   frame   guides   to   ensure   things all   matched   up   as   he   stood   aloft   and   steered   the   curb   in   its descent into position (fig.10). 

Fig.5

Fig.6

Fig.7

Fig.8

Fig.9

Fig.10

The   cargo   straps   used   to   lift   the   curb   can   be   seen   in   fig.9   and to   prevent   them   being   trapped   underneath   the   frame   when   it was   lowered   wooden   spacers   were   placed   on   the   bricks.   They were   then   pulled   out   by   levering   the   curb   up   to   free   them. Adam   drove   the   4’   long   bolts   down   through   the   brickwork   and tightened   the   nuts   against   the   oak   pads   set   in   the   top   floor   wall (fig.11)   pulling   it   firmly   down   onto   the      tower   top.   The   heavy duty    waterproof    cover    we’d    designed    and    had    made    from ‘curtain-sider’   material   was   fitted   over   the   curb   and   frame   and tied   down   securely   to   the   tower   ring   bolts   in   the   fast   fading light.   It   was   very   satisfying   for   us   to   have   finally   made   a   start

on   replacing   the   mechanism   of   the   mill   and   for   that   we   have   to thank Adam for his invaluable diligence and expertise.

 Fig.11

With   the   curb   installed   our   collective   attention   now   turned   to the   next   major   requirement   for   completing   the   project   -   the two    largest    individual    castings:    the    windshaft    and    the    iron cross.   We   emphasized   from   the   start   our   plan   was   to   restore the   mill   to   its   true   original   appearance.   To   make   this   possible Adam   had   been   searching   the   windmill   community   trying   to locate   a   second-hand   Lincolnshire   type   windshaft   rather   than

the   pole-end   type   used   elsewhere   but   was   finally   forced   to admit    defeat.    This    meant    a    new    one    had    to    be    cast    and therefore   a   pattern   would   have   to   be   produced   for   the   foundry. The   method   adopted   was   to   create   a   half-pattern   as   shown   in fig.12   mounted   on   a   back   board;   this   would   be   used   twice   to produce   two   half-moulds   which,   when   fastened   together,   would provide a full mould for the molten metal see fig.13.

readying   both   units   for   collection.   The   pictures   hardly   do   justice   to the    size    and    weight    of    these    two    vital    components;    quality engineering   produced   in   Yorkshire   by   H   Downs   &   Son,   Peacock Works, Huddersfield.

Fig.12

Fig.13

Fig.14

Fig.15

Fig.16

Fig.17

We    now    had    brand    new    metal    castings    (figs.16&17)    specially designed    and    made    to    fit    into    the    new    cap    which    Adam    was constructing   for   the   mill   instead   of   making   do   with   second-hand items.   Needless   to   say   there   had   been   delays   and   hold-ups   along the   way,   due   in   part   to   the   lock-downs   imposed   because   of   Corona Virus,   but   Adam   kept   pushing   the   job   along   to   the   best   of   his considerable   abilities.   His   next   task   was   to   arrange   machining   which was   going   to   present   problems.   Workpieces   of   this   size   and   weight take   some   maneuvering   and   need   a   very   special   lathe   (fig.18)   to

accommodate    them.    The    accuracy    of    the    bearing    surfaces    is particularly   important   in   the   case   of   the   windshaft   to   ensure   the smooth    running    of    the    sails.    Adam    entrusted    the    work    to    HMS Engineering   Ltd.,   Hereford   who   were   also   involved   in   devising   the optimum method for keying the shaft to the cross. While   all   this   was   taking   place   the   bronze   head   and   tail   bearings (figs.19&20)      which   will   carry   the   weight   of   the   windshaft   and   cross were being cast by a specialist foundry AJD Foundries Ltd., Dudley.

Fig.18

Fig.19

Fig.20

Now,   with   the   castings   well   on   the   way   to   completion,   we   can   catch up   on   the   major   woodworking   taking   place   at   Adam’s   yard.   He   had been   busy   locating   suitable   pieces   of   oak   (fig.21)   to   fashion   into   the weather   beam,   sheers   and   other   components   of   the   cap   frame.   With these   items   in   stock   large   scale   carpentry   and   joinery   skills   were employed   to   joint   and   assemble   the   main   framework   of   the   cap       

base.   Slowly   the   outlines   became   clear   and   the   (fig.24)   shows   the cap frame and the gallows for the fantail all in position.

Fig.23

Fig.21

Fig.22

Fig.25

Fig.26

When   we   began   our   project   to   rebuild   Muston   windmill   we   had   no   illusions   about   the   size   and   complexity   of   the   task   we   were undertaking.   The   story   of   our   struggle   to   first   obtain   planning   permission   and   then   organise   the   rebuilding   of   the   tower   is   told   in   the preceding   pages   of   this   website;   however   we   felt   that   those   readers   with   a   more   specialised   interest   in   windmills   would   find additional   detail   regarding   various   engineering   aspects   of   the   work   valuable.   In   an   effort   to   cater   to   their   needs   we   have   added   a Technical Blog page to the site.

Back to the Top

Powered by Xara Web Designer

Fig.27

Fig.28

In   photograph   fig.27   we   can   see   two   of   the   last   large   timbers   being worked   on.   They   are   the   spars   or   technically   speaking   the   ‘spears’ that   are   mounted   on   the   gallows   and   support   the   fan.   Fig.28   shows the    four    castings    known    as    ‘pigs’    on    which    the    cap    frame    is

mounted;   they   support   the   weight   of   the   whole   cap,   sails   and   fantail assembly   while   sliding   round   on   curb   as   it   rotates   in   the   wind.      One   of the    really    important    maintenance    jobs    essential    to    the    smooth running of the mill is thickly greasing this load-bearing surface.

To be continued…