Restoration Update - March 2013

Just a few photos to give you an update on the progress of the mill restoration work
Sail photos by Steve Boulton, Millwright. Mill photos by Simon Heath, Museum Trustee.

Sail no.1 bars fitted 

One sail down three to go

Stock clamps

Concrete floor in process of being removed. It will be replaced by a more sympathetic wooden floor.

Scaffolding has been erected for the removal of the external rendering.

Patches of rendering removed exposing the clunch beneath it.

Patches of rendering removed exposing the clunch beneath it.

www.burwellmuseum.org.uk

BURWELL MILL FINALLY DECAPITATED…

The weather was perfect on Wednesday morning (13th March) when the cap was finally lifted off Burwell Mill. A hugely supportive crowd of local people, mill enthusiasts, Friends of the Museum and volunteers turned up to watch (including a class of fascinated under-fives from Burwell’s Spring Close Montessori school) and were served tea and cakes from the viewing point on Mill Close. 

First the temporary roof was swung over the Mill by the mobile crane, looking like a shot from a sci-fi movie against the bright blue sky. An hour later, after much hard work by the millwrights Neil and Steve, the cap was tenderly lifted off by crane driver Darren, and set on the ground to cheers, whistles and applause. 

Anne Mason, Heritage Lottery Fund Committee Member for the East of England, gave a excellent speech about the Fresh Wind in Our Sails project which was enthusiastically received. It was a great day, and thank you to everyone for your support!

Photos of the day are in a slideshow below.
To view the photos full-screen click here 

Video by Peter Heath
(video available in HD - start playing and then click the "Change Quality" symbol in bottom right of video frame)

(To watch in full screen - double click on video)

THE DAY IN DETAIL…
Earlier in the week the two millwrights, Neil and Steve, made preparations for lifting the cap off the Mill to ground level, an operation that was achieved on Wednesday morning in near perfect weather conditions.

The first task of the week was to assemble the temporary roof to keep the mill dry until the cap can be refitted later in the year. This is a light timber lid with a small eaves overhang that is covered over with roofing felt. An important element of the lid is a hatch to allow the four lifting chains to be attached and detached. The temporary roof was brought to site in sections and assembled in front of the mill where the cap was due to land. A 45-ton capacity four-wheeled mobile crane arrived on site early on Wednesday morning, driven by Darren of Welch’s, Cambridge, who works with many local mills. Soon after 8am, the crane took the strain as the temporary roof was lifted high over the mill to create more space in the compound. One of a pair of millstones displayed outside the Mill was also lifted out of the way by mechanical means.

Back at the top of the Mill, the storm hatch at the front of the cap was removed. A chain hanging from the crane hook was then attached to the empty cast-iron poll end of the windshaft. Inside the cap, several straps had been added to prevent the windshaft lifting free of its bearings when tension was applied to the front hanging chain. Two more chains were connected to the projecting sheer overlays that form the fan stage at the rear of the cap, forming a three-point lift. Adjustable pulley blocks on each of the three chains allowed the millwrights to level up the cap precisely as the crane gradually took the weight of the six-ton structure. Two control ropes reaching to ground level were tied to the cap at front and rear. As it was slowly lifted clear of the tower shortly after 9.30am, the natural rotation of the cap in the light breeze was checked by assistants holding the control ropes.

The cap hovered approximately one metre above ground level for several minutes while a supporting nest of timber blocks – looking like a large Jenga set – was constructed. Its final few centimetres of descent were covered at a snail’s pace with the millwright checking all sides to ensure that the cap’s internal frame rested evenly on its new foundation. 

After a well-earned cup of tea, the temporary roof was lifted on to the tower and securely strapped to the internal beams to prevent it lifting during gusty conditions. The final craning operation was to lift the six-bladed fantail from its bearings at the rear of the cap and lower it to ground level so it could be dismantled and repaired.

A large crowd of visitors, refreshed with cakes and tea laid on by the Museum, watched the lifting operation. Those who arrived with seconds to spare were greeted with the sight of the cap in mid-air as they approached. Once at ground level, the condition of the aluminium sheet covering and fan stage timbers could be inspected. Among the visitors was Chris Wilson, restorer of the windmill at Over, who had been commissioned to rebuild the cap in situ and install the aluminium covering in the late 1970s. Chris was pleased to see his handiwork still in a serviceable condition after 35 years’ exposure to the elements, and brought with him some wooden patterns for the metal components of the fantail gearing that he had made. 

With the cap now accessible at ground level and new sails under construction at their workshop, the millwrights have plenty of work to get on with and have already made excellent progress. Over the coming months the aluminium sheeting will be stripped from the cap rafters, the fan stage will be repaired and the fantail gearing will be overhauled. New cedar weatherboarding laid vertically over the rafters will return the cap to its traditional white-painted appearance. The result will be stunning and is eagerly awaited. 

Fresh Wind in Our Sails team

Links to local media reports on Cap Lif-Off Day
East Anglian Daily Times 
BBC News - Cambridgeshire
Ely Standard
Cambridge News
Ipswich Star

www.burwellmuseum.org.uk

BURWELL MILL DECAPITATED WED 13TH MARCH, from 9.30am

The big day has finally arrived – the cap is being lifted off Burwell Mill by a 65-tonne mobile crane from 9.30am. It’s a historic day for the village, so please come along and bring your friends and family – refreshments will be provided. All are welcome!

Getting the cap off the Mill is no easy matter! During the lifting operation, the crane’s extending boom will be positioned high above the Mill. The 6-ton cap will be lifted off and placed on the grass beside the Mill. Finally, a temporary flat roof will be placed on top of the Mill, to protect it from rain while repairs are being carried out.

It’s part of the Fresh Wind in Our Sails restoration project, funded by the Heritage Lottery Fund (HLF). Anne Mason, HLF Committee Member for the East of England, will be in attendance during the morning,  and will say a few words about the event and the Fresh Wind in Our Sails project.

Look forward to seeing you there,

Fresh Wind in Our Sails team

Temporary roof ready to go on the mill on Wednesday

The mill & museum entrance on Tuesday evening

 Photos by Simon Heath

www.burwellmuseum.org.uk

New Sails

Our Millwrights are busy making new sails at their yard in Alford, Lincolnshire. (Click on a photo for larger version. Photos by the millwrights.)

Neil Medcalf fabricating striking gear

Neil cutting rules (shutter bars)

Neil marking out the laminated whips for the first new pair of sails.

Steve Boulton planing shutter bars

Steve morticing the whips

www.burwellmuseum.org.uk

Cap Coming Off

Come and watch the cap of Stevens' Mill being removed as part of the Heritage Lottery funded restoration.
From 9:30am on Wednesday 13th March.

www.burwellmuseum.org.uk

Sails-Off Photos & Video

Two days of hard work from the basket of a cherry picker resulted in the removal of the windmill’s sails on 13th February. Neil Medcalf and Steve Boulton of Traditional Millwrights Ltd laboured in cold conditions to extract the fixing bolts and wedges that held the sails in place.
More info below video box.

Click this photo to see further photos from the day

Thank you to Luke Bonwick and Peter Heath for the photos


Video - by Peter Heath
(video is available in HD if you select Full Screen - click the symbol in the bottom right of video frame)

The first task was to rotate the sails and their supporting windshaft, which had not turned for several years, through 180 degrees to bring the uppermost sail to the bottom. This one would be removed first. On the morning of 13th February, a mobile crane arrived at the site and was positioned at the head of the track from Mill Lane. Its long jib was extended high above the mill and from it the lifting hook was lowered into position for the removal of the striking rod. The rod is part of the operating gear for the sail shutters and, before the sails could be removed, it had to be slid forwards out of its working position at the centre of the cast-iron windshaft.

With the rod and four-armed ‘spider’ coupling safely at ground level, the lowest sail frame could be removed. This was a fairly straightforward procedure, achieved by extracting each of the four fixing bolts with the weight of the sail hanging from the crane hook. Once safely at ground level, the condition of the timber could be examined at close quarters. Large areas of rot could be seen at most of the major joints of the sail frame. The effects of the driving wind and rain had caused the timber to begin breaking up. Its removal was timely, as it is unlikely that the sail would have survived many more winters without totally disintegrating, and possibly ending up in a neighbour’s garden! 

The next lift was more ambitious, as the millwrights planned to remove the second sail and its supporting stock in one go. This involved positioning the crane hook above the centre point of the sails and attaching it at the correct point of balance to achieve the lift. When everything was ready, the wooden wedges that held the stock in position were knocked out. With no wedges in place, the stock should theoretically be free to move in the canister – the open-ended box casting at the front of the windshaft.

It was found that the stock had absorbed some rainwater over the years since it was fitted, and this had caused the timber to swell slightly near its centre point. With the crane jib applying tension the stock would only move upwards a few millimetres, despite strategic rocking backwards and forwards with the aid of ropes to try and release it. Its increased thickness meant that the stock could not pass through the canister until the millwrights had removed the excess timber with the aid of a power planer and an extra-long chisel. With the swollen area removed, the crane jib applied tension again. The lifting cable hauled the hook upwards until the stock and sail had been lifted clear of the mill and could be lowered to ground level. 

The final part of the operation was to load the sails onto the trailer of a waiting flatbed lorry for transportation to the millwrights’ yard in Lincolnshire. This was easily achieved with the aid of the lorry’s remote-controlled lifting arm which carefully avoided an inconveniently-placed lamp post!

The millwrights expect to complete the next stage of the project, the removal of the cap and fantail, before Easter.

Sails are off!

After the weather delayed work for a few weeks, Wednesday morning saw the mill sails being taken down. They have now been taken to the millwright's workshop in Lincolnshire for repair.
Photos and a video of the removal of the sails will be published very soon on this Blog and on our website www.burwellmuseum.org.uk .
The mill cap will be taken down on Wednesday 13th March (weather permitting!).