This is day four of waterwheel building. We've seven buckets in place and the last row of holes to drill on the seventh bucket. The location holes for the bottom edge of the buckets are already laser cut but the holes through the shrouds need to be drilled.
Stainless steel work hardens very quickly and burnt out drills are a likely outcome if they are not drilled at the right feed rate and speed. In practice high-speed steel cobalt drills with a drop of lubricant do the job very well indeed provided the speed is slow and the pressure fairly high.
Hopefully, not a shroud to be buried in rather the name given to the stainless plates that form the inside of the waterwheel and make the bottom of the buckets. These stack one above each other and are bolted in place with stainless steel bolts.
The buckets are held onto the cast iron wheels and drilled and bolted into place on the shrouds.
Here we are with the magic complete. We set a day aside to get the gearbox in place on the end of the drive-shaft. It was a bit daunting on the face of it because it weighs in at 600kg and is a big lump of a thing. Thinking time was important here because the downside was going to be painful financially and the potential danger to body parts was significant.
The gearbox had arrived some months previously and was bolted into a big steel crate which we moved about on a pallet truck. It had to go down nine inches into the gearbox pit and be mounted onto the drive shaft. We constructed a pair of wooden ramps with a brick under the center of each plank. We fitted two bent scaffold posts on top of these ramps and slid the gearbox down them half an inch at a time with the aid of a big stick. The bent scaffold poles couldn't roll off the ramp and they made it possible to get the big stick between the gearbox and the ramp to slide it incrementally into place. The brick in the middle of the ramp meant that we could pivot the ramp to lift the gearbox into place.
The gearbox has a hollow shaft that fits onto the drive shaft and is jacked into place by a 22mm drawbolt.
The whole thing was done and finished and we were drinking the first morning cuppa by ten thirty.
Here is the method by which the wheel assembly was lifted. The idea is to pick the oak beam up and place an engineering brick under it. The key point here is that the jack at the extreme right of the photo has to lift the oak plank which in turn lifts the strap that lifts the beam upon which the waterwheel stands. This is merely a quarter of the total weight of the assembly so about two tons.
The brick was just the right size and certainly strong enough. The short plank of oak took the strain albeit with a bit of a bend.
In order to clear the old, worn out plain bearing located in the wall we needed to raise the waterwheel assembly a bit. In practice the width of a pencil. The tip of the marking gauge has moved from the top of the pencil to the bottom as the assembly was lifted clear of the old bearing. At this point, the waterwheel was loaded onto two new roller bearings for the first time.
When this was complete the six-ton waterwheel could be moved easily simply by hand pressure. It also became clear that the whole assembly was almost perfectly balanced.
The main bearing shown here replaces the worn out plain bearing mounted in the wall behind the pit-wheel. This is a modern rolling element bearing that is capable of high speeds and very significant loads. The manufacturers think it will never need replacing as it is doing "trivial" duty.
The bearing is fixed to the shaft by an expanding collet and it sits upon a huge oak beam that will be lifted onto engineering bricks at each end with a void below to give a bit of vibration isolation. It is shown here standing on a block of oak.
The outside main-bearing was a plain bronze bearing that was in a sorry state of repair having very little to offer. Notwithstanding that we made up a sleave to repair the damage to the end of the shaft that would support a new "posh" roller bearing. This sleeve was to be glued in place with an epoxy resin-based compound called belzona.
Well, by evening, we have our new doors in place. These were made by Andrew Jaynes Joinery in Canterbury. They are CNC precision engineered items made from ACCOYA particularly special having a full height curved section that fits the opening perfectly.
We would certainly recommend Andrew Jaynes to anybody. They specialize in ACCOYA because it's stable, rot-proof and easy to machine. TRADA guarantees the material for 75 years. For windows and doors that means a perfect fit every time no matter what the weather. It needs no treatment and yet takes paint very well indeed when required. The paint is far less stressed because the stability means the paint is not stretched and shrunk as it would be on a material like oak which changes dimensionally throughout the seasons.
Here the drive flange is in place prior to final adjustments and a few bolt changes.
It was particularly rewarding to discover that the drive-shaft was only three-thousandths of an inch out of alignment when the pit-wheel was rotated. A remarkable result considering the pit-wheel is 88" in diameter and sits on the end of a11.5" shaft that was made over a hundred and fifty years ago.
This looks like a very small item from a watch or clock mechanism; in practicethis is a four-man lift.
Here we are with the mag-drill. Cast iron pit-wheels don't have much magnetism so we had to rig up a steel plate in the right place that was clamped onto the flange so we could drill the holes for the drive flange. These holes are 26mm diameter and about 65 mm deep - not a black and decker activity.
This is the main coupling to the gearbox. The Flange is in itself a two-man lift.
The drive flange is incomplete at this stage but it was necessary to "find" the holes in the pit-wheel so we could drill them in the right place. The flange then goes to have the drive-shaft welded in place and the whole assembly is fitted at a later date.
Here's a view of the old main bearing sitting in the wall of the mill. This is a bronze plain bearing with no cap that has been open to the elements for a long time. There was precious evidence of lubrication and the journal is in a chronic condition. The plan is to leave it in place but lift the wheel a few millimeters and support it on new rolling element bearings at either end.
We can then brick up the wall to seal the building from the elements.
Here you can see the three new windows in the north face. We worked with Robin Uff the (now retired) conservation officer on the design of these windows. We have a very traditional horizontal sliding sash design that was very common in Bedfordshire. These are often referred to as "Yorkshire sliding sash windows".
Here are Don and David fitting the new sluice gate. Don has designed a rack and pinion system to control the water flow. He has followed traditional practice carving the engineer's name (that's Don) and the year into the front panel. The water is held back by the stop boards further back since the dagger-boards for the new sluice gate haven't been installed yet. Even with low flow rates the fine sheet of water is evident as it flows over the tray it resembles a sheet of black plastic.
Bedfordshire drainage board finished dredging the river last week and we were keen to try the new sluice tray. Shifting thirty years of accumulated silt is challenging. As we lifted the stop boards we were rewarded by a beautiful clean flat sheet of water flowing over the new sluice tray.
The water is running properly again after a very long time resting. We continue to excavate the tail race by hand and hope to render the waterwheel "dry" ie running with clearance below the buckets rather than flooded which loses efficiency.
All of the mill furniture has been ravaged by woodworm and some of it is barely hanging together. This hopper in particular was in a bad way and has needed wood glue and filler in places to hold it together. The millers mended things using tin and lots of small tacks so the same technique has been used to mend the corner of this hopper. The tin is already rusty because it had been used to mend a rat hole in one of the grain bins.
Here are two hoppers resting on the top of the Victorian tun. The hopper on the left has just been treated with woodworm killer. The one behind has been treated with both woodworm killer and white colour stain. The colour stain will ensure that the colour remains the same instead of going orange when the shellac and furniture wax is applied.
There are three pairs of stones in the mill. The original pair were driven from the waterwheel. Another pair was added later, probably by the Victorians and were driven by steam. These millstones have a hexagonal tun whilst the others have round barrel-style tuns.
Here you can see the Victorian tun gently sanded and painted with woodworm treatment on the top.
The new sluice is made of of Accoya. The tray curves very slightly to direct water into the waterwheel buckets.
Accoya is a remarkably stable material used extensively in the waterways of the Netherlands. It is is guaranteed to last 25 years submersed in water and 75 years as a cladding material.
Finding the right bolts to hold the new buckets onto the waterwheel has taken some time and a sample or two along the way. Here we have a stainless steel bolt combined with a tapered SG-iron washer that matches the geometry of the grey cast iron waterwheel flanges the washer ensures that the fixings operate properly.
The corner window was installed by expert fitters from Andrew Jaynes who manufactured the windows. It achieves exactly what we wanted of it - the timber structure of the mill inside is clearly visible from the outside. This is a particular favourite of our recently retired conservation officer, Robin Uff.
We were originally going to use a larch or oak weatherboarding that would have been painted with a proven long-lasting exterior paint. Then we discovered Accoya. The ultimately superior properties of Accoya result from a process called Acetylation.
Accoya is a wood that is almost inert, immune to bugs and even immersion in water. It's TRADA guaranteed for 75 years. The colour was an unexpected bonus since it is so close in colour to the paint that was originally on the mill. It will pale and 'silver' with age but won't need any maintenance for many years.
Accoya also works beautifully for making the windows. It is stable enough that we can make the glazing bars that are just as thin as the existing windows even though they are holding double-glazed panels. So we get low maintenance low energy windows that don't need to be painted, will match and age at the same rate as the weatherboarding and will still open and close smoothly after 10 years of being battered by rain and condensation.
Nick runs a tight ship with super attention to detail. We had a great experience when Flitwick Roofing did the work on the Forge and Garage buildings and we had no hesitation in getting them back. If you want a good job well done go find a busy man. He's busy for all the right reasons.
You can raise Nick on 07792 331536
The critical load bearing structure of the south wall above the hursting frame was largely swept up in the vacuum cleaner. The wall plate had gone completely in places and we elected to replace it in oak. The wall plate now supports new Studwork beneath a new supporting horizontal beam above. It was a big relief when we removed the acro-props and nothing happened.
Here we are a few days after the concrete was poured. Removal of rotting timbers started to reveal the medieval wall of the 1720 mill. It also compartmentalises the milling process nicely. Gravity takes corn from the top floor, to the stone floor and deposits it on the ground floor beneath the mill stones into sacks.
The concrete lorry arrived on our custom made road. This was 44 tons fully loaded. The road was necessary because our lovely neighbour thought he was gaining leverage over us by blockading our rightful access to our front door with motor vehicles and heavy planters. The job simply went on and the neighbours bargaining chips diminished.
The erosion of chips continued as we used the roadway to load stone, sand, insulation drainage and reinforcing materials enabling the mill floor to be constructed.
We made some rather disturbing discoveries along the way. The decades of neglect and almost wanton destruction due to water ingress have taken their toll on the ground floor and anything within. it was clear that we needed to prop a lot of things up during foundation works - and beyond.
This shows the north-east corner of the hursting frame after a new lower cross-brace has been fitted. The degradation of the foot of the post is clear - the vacuum cleaner has done a good job!
The whole of the east end of the husting frame was unsupported and the mill stones were indeed about to fall into the room below. The oak blocks here will be replaced with engineering bricks and the stump at the lower end of the post will be tidied up properly. At least the collapse has been halted.
This image shows the view from below of the north east upper hursting frame repair. This joint supports the cross beam under the mill stones which sit directly on top of these two timbers.
Rot at the bottom of the vertical post caused it to drop and the weight of the millstones rendered the end of the oak beam assunder - this is shown elsewere.
There was no possibility of replacing the whole of the longitudinal member and it was decided to simply graft on another chunk of oak and bolt it to the beam behind it. The beam behind also made it impossible to fit a true mortice so this is constructed in two sections split along the length as shown.
The mortice was routed in the top half of the extension to the longitudinal member and a second chunk of oak was fashioned to fit into the existing joint and mate with the tenon. These two oak sections where then bolted together and the pair then secured to the beam behind with large coach bolts.
This image shows the damage to the longitudinal member at the north east top corner of the hursting frame. The end of the member has failed as the vertical post supporting it has rotted away.The mortice and tenon joint at the end of the hursting frame horizontal beam simply failed. It is surprising that the whole Mill stone assembly didn't collapse into the floor below. Urgent repairs were the order of the day.
This shows the East end of the hursting frame back in place with the new lower brace fitted and the laser line showing it to be correctly in plumb. Both posts are now firmly back in their respective places with the mortise and tenon joints back together. There was a time where both posts were hanging in mid air from bits of rope secured from above. It was the only way to get the lower joints together and provided a challenge that precluded a photo shoot.
The lower brace is temporarily supported on oak blocks and the missing lower ends of the posts are clearly in evidence.
This is a substantial piece of oak. It replaces the the old one which had almost rotted away completely - certainly well beyond the point of usefulness. The tenons are 3"x8" and the section is 12"x15" fitting will be a juggling act with substantial posts to support and gentle nudging into place with a fourteen pounder. When it's in place it will take the vertical loads that supports the whole of the east end of the hursting frame and the eastern pair of mill-stones.
This is like a scene from the battle of the Somme. It actually shows the internal drainage along the North wall of the mill. The foundations are completely saturated at this point in time. The ground water level in this space was less than two feet above the river outside. The drainage inside the mill has transformed this situation.
The forge is a chance to try out many of the materials and methods that we will use on the mill. This includes the insulation regime.
Here you see a good thick layer of wool lining the walls. What you cannot see is the space age, breathable multi-foil insulation layer just under the weatherboarding. We're already surprised at the difference it all makes to both noise and thermal performance.
When we found this enamel sign in the mill, it was so dirty that we thought it was just one of a number of sheets of rusty metal.
The sign is advertising animal feed from a company called R&W Paul Ltd, an Ipswich based company founded in 1842. The brewery diversified into the manufacture of animal feedstuffs after 1877.
The company was eventually sold to the Irish-based agriculture and sugar conglomerate, Greencore.
Oakley framers work as a well oiled team. They don’t stop but keep up a steady relentless pace moving heavy oak posts and beams. The four of them loaded and unloaded 9 tons of garage materials and drove down from Corby all before 11am. By evening the oak frame was up.
“Weeping walls" can be impregnated gently with slower curing mixtures of resin. The water is effectively pushed out of the wall as the expanding resin “freezes” forming a waterproof structure inside brickwork and replacing water and lost grouting.
As this barrier cures, the pressurised resin bleeds backwards to the near side of the wall where it leaks out of every nook and cranny as it forces the water from the wall. The curing resin is shown dribbling down the wall. These white rubbery streams are easily removed when the resin solidifies.
After six months the wall is now dry and happy. The whole building is far more airy and theres a feeling of warmth in the place that’s never been there before.
The team from Oxford Hydrotechnics injected a hydrophobic resin that is thinner than water into the structure of the wall. This is a common cure for serious leaks in tunnelling applications encountering subterranean water.
The resin can be brewed to cure at different rates. When the resin meets water it reacts by rapidly expanding up to twenty-fold in volume. Big leaks can be quenched instantly by quick acting resin that forms a waterproof flexible foam that fills large voids and blocks large holes.
The fountain mixer is a two-storey steel drum that stretched from the walkway at the top of the building and ends in a funnel shape on the first floor, having passed through the bins floor. It is a relatively modern agricultural machine that was typically used to add moisture to the corn prior to grinding it.
We've closed the mill gates to stop the flow of water over the waterwheel. Now that the wheel has dried out, we can remove the rusting buckets and start to renovate the wheel, ready for new buckets to be installed. Once the buckets have been removed, we'll be able to inspect the wall behind and remove whatever had stopped the wheel from turning. When the frame has been renovated, we'll install new buckets and then look at renovating the mill gates and mill tray.
The builders did a great job of making the door look in place and in character. In fact, this isn't the final door, it's a temporary and very sturdy one that will be there during the renovation.
Once the renovation is complete, it will be replaced with a door that is even more like the original front door to the mill.