Tuesday 13 December 2011

The launder end completed

For the last couple of weeks the weather has been poor, and Ray has decided that crossing the Pennines in possible heavy snow would not be a good idea. It has therefore been left to Richard and me (Bob) to finish off the launder end. We did this even though it involved cutting wood, a job we usually leave to Ray.

Today we cut the last 4 or 5 pieces, including the boards that extend the base of the launder, and the angled side panels.

The finished job can be seen in this photo - the boards of the wheel can just be seen through the gap where the water is supposed to fall through. The gap leads to a short rectangular tube that is wider than it looks, but is angled back towards the launder to deflect the momentum of the water.

We tested the wheel rotation, and found that one of the new boards just touches one or two ofthe buckets, so we will have to take that out and plane it down a bit - another job for Ray!

Tuesday 29 November 2011

Modifying the end of the launder

Richard has now finished fabricating the iron framework to carry the modifications to the end of the launder. The idea is
  1. To carry the water further so that it will enter the wheel at a higher point, so that it will be falling as far as possible while it is in the wheel
  2. To deposit the water at a better angle so that its momentum is not acting against the motion of the wheel
  3. To add side cheeks to stop the water splashing out of the wheel

View from the launder showing the brackets
and the side cheeks

Another view showing one bracket and side cheek

Sunday 20 November 2011

General maintenance

Since the season ended, we have been doing a few small jobs and preparing for bigger ones to come.

We had a long-ish meeting with Sara to agree what the programme of work should be.
We had a good tidy-up in the workshop.

Richard fabricated one of the metal structures to modify the end of the launder and we tried it in place.

Ray inserted a small strip of wood onto the end of the launder bottom so that the lip is now parallel to the wheel.

We made a trash strainer out of chicken wire for the mill end of the head race.

We dismantled the stone furniture and hoovered out the generous layer of flour stuck to the inside.
We measured up for the timber we need to repair the launder and to re-line the wheel.
We designed a grain storage bin.

Monday 24 October 2011

Meeting the Traditional Corn Millers

On Saturday 22nd, Richard, Bob and Sara Braithwaite (custodian of Acorn Bank) were invited to join a meeting of the Traditional Corn Millers Guild. They were at Little Salkeld watermill for one of their two annual meetings, hosted by Nick and Ana Jones. We met them for afternoon tea and to watch an excellent 30 minute film that they had commissioned.

On Sunday morning it was their turn to visit us at Acorn Bank. We started the mill early and set about milling our last 25kg bag of grain. Having all those experts around made it both slightly embarrassing and extremely helpful to encounter one or two new problems.

The first was that we seemed to be unable to get enough power to produce flour, until it was pointed out that the stones can be "choked" if grain is delivered too fast ("you are literally grinding to a halt!"). A reduction in the feed produced an immediate improvement. In fact we were able to reduce the water flow after the machine had "warmed up".

Secondly, there continued to be whole grains in the product. These turned out to be missing the grinding process due to scatter from the bottom of the damsel bouncing them across the top of the stone. It is strange that this has not been a problem before.

Thirdly, we continued to have difficulty with the grain feed from the hopper to the shoe - either it ran too fast and overfilled the shoe, or it didn't run at all, giving a threat of running "dry". This needs constant attention. Others reckoned that their hoppers sit in the grain in the top of the shoe and therefore don't run if the shoe is full - like a budgie seed feeder. We will try to rebuild the shoe and the support for the hopper to give this effect.

We were very pleased that the professional millers generally approved of our efforts, and Mike Thurlow, Miller at Letheringsett Watermill said "What you have done with that pair of stones is excellent - I think you all should be very proud of your achievement.". We were also very grateful for the free advice they so generously gave. Thanks, traditional corn millers!

Tuesday 18 October 2011

Odd jobs

Last Sunday was Apple Day, but was rather reduced due to the parking fields being waterlogged. However, loads of people turned up and we (Richard, Sylvia, Bob and Stuart from Heron Mill, who kindly spent the day with us) milled more-or-less all day, in spite of a slight and rather ironic shortage of water. More than 370 visitors came to see, many of them drawn by the TV coverage.

Today we did a few odd jobs.

To begin with, we tried to work out how best to modify the end of the launder to make the water fall into the wheel at the correct angle. Richard is going to make a frame from angle iron to carry the extra boards, and we made a plywood template to guide him.

The hopper lid and feed shelf

We also made a tongue-and-groove lid for the hopper, to keep the bat poo out. This will be usable both between and during millings. We also fitted a shelf in the rail between the upper and stone floors to help with tipping bags of grain into the hopper. We positioned it halfway between the No 1 and No 2 stones so that it would also serve a hopper for the No 1 (shelling) stones were it to be needed. Hopefully this will avoid tearing the bags, as happened on Apple Day.

Richard attends to the grease

Finally, we cleared out the old, waterlogged, grease from the wet-side wheel bearing and replaced it with new grease.

Monday 17 October 2011

Stars of the small screen

Here, with the kind permission of BBC Look North for North east and Cumbria, is the TV news report about the mill, broadcast on Wednesday 12th October. Our thanks go to their Colin Richardson.

Tuesday 11 October 2011

Milling again

Today we were inundated by BBC reporters, well, two of them anyway. First a radio man with a fancy recording microphone, then a TV man with a very fancy Sony camera. They both spent a couple of hours with us, interviewing, recording and watching us mill our second batch of flour - the first time we have milled on our own. The TV report was supposed to go out on Tuesday evening on Look North, but it didn't. Someone told me it went out on Wednesday lunchtime, and it certainly went out on Wednesday evening. The radio report was due to go out on Wednesday morning, but as I can only get digital radio, and Radio Cumbria only does FM, I have no idea whether it did.

The milling was successful, however, and we ended up with a few more Kg of smooth flour even after we had given samples to the BBC men.

Later, we finished the work on the new dump valve system. As the video shows, it worked quite well at first, though we later had to remove some of the rubber seal around the dump valve, as water pressure drove it into the mechanism, causing it to jam.

Tuesday 4 October 2011

Developing the water control

During the last week, Richard had fabricated a superb, flexible hinge arrangement for the new second lever on the dump valve. Today we installed the hinge, with the new lever, through a new hole in the weatherboarding wall. The hinge is mounted on the weatherboarding, which is reinforced by a large plank screwed across several boards. There is adjustment of the axis of the hinge relative to the wall, to allow for the slight skew angle of the launder.

We then made the two-piece link to join the new lever to the old, assembled the whole thing (apart from the actual shutter board) and tested it. This short video shows how the new lever moves further than the old one, as intended.
At last this damned Blogger interface has let me upload it.

Elsewhere, we also fitted a couple of small pulleys to re-route the cord controlling the angle of the shoe so that it can be adjusted from the lower floor.

The following day, Wednesday 5th October, Richard and Bob returned to the mill, lured by the prospect of a visit by the BBC - which, typically of the media, never happened. However, we did manage to test the new shutter with the board rigged approximately in place and to clear some of the woodland debris from the headrace. Richard also made a number of measurements for his ongoing home fabrications.

Thursday 29 September 2011

Improving waterwheel control

While Nick Jones was helping us to mill our first flour last week, he observed that we could do with a bit more power from the wheel, as well as the ability to control wheel speed from inside the mill. This control might be done by the dump valve, a board we can drop out of the bottom of the launder. We also noted that the dump valve was not effective as an emergency stop when the water flow was high - enough water just 'toboggans' over the dropped flap to keep the wheel turning.

So today we set about improving the action of the dump valve. The options were either to make a second board drop, doubling the width of the gap, or to link a vertical board to the dump valve mechanism so that it forms a block across the launder just below the dump valve. Dropping a second board would be a major engineering project, so we concentrated on the second option. The main difficulty was that the available lifting motion from the dump valve mechanism at the point where the new board needs to fit was only about 9cm, and we would need nearer 20cm.

After exploring many ideas, we concluded that the only way to generate the extra movement is to use a second lever linked to the dump valve actuator with its own separate pivot. We cobbled together an experimental rig using a hoe handle with its pivot in the weatherboard wall of the wheel shed to check the theory and it worked, as the pictures show. Parts of the permanent mechanism will be made over the next few weeks.

We also noted several issues that may affect the efficiency and power of the waterwheel. Firstly, it leaks badly, and stopping water escaping from the buckets would increase power. Secondly water splashes out of the first bucket due to the height from which it falls from the launder. The side cheeks we noted at New Abbey might help, however we also noted that the end of the launder is not parallel to the axis of the wheel. Finally, as the wheel is pitchback, the water falling from the launder is moving in the opposite direction to the wheel and therefore its horizontal momentum will act as a brake. We began to design a box for the end of the launder to reverse the direction of the final fall of water.

Tuesday 20 September 2011


At last, after 4 years of work, we finally milled!

This was the first time since at least 1940 the mill has produced flour
We make the final adjustments...

We arrived early to make sure all was well, and made a few minor changes and adjustments. Nick Jones, from Little Salkeld watermill, arrived with two sacks each containing 25kg of grain. After a few further checks, he took us through the process of starting up for the first time. A lot to learn, from how to untie the paper sacks easily rather than fighting them, to balancing wheel speed and grain flow rate to get a good product.

...before Nick Jones arrives
to fill the grain hopper

In the event the product was proclaimed to be good and the whole thing worked smoothly, surprisingly so for a first run. We had a small celebration and carried on milling for a couple of hours. Nick reckoned the system could be run faster to increase output, but that isn't really a problem for us, we don't want tons of the stuff!

The short video shows some of the bits of the process in action, with nice mechanical sounds.

Monday 19 September 2011

Visit to New Abbey Mill, Dumfries

The New Abbey waterwheel

The stone floor

This year's Acorn Bank staff and volunteer outing took us to New Abbey Mill (also to Threave garden, a very interesting and pleasant place, but a garden blogger will have to write about that).

New Abbey Mill is a single wheeled watermill with 3 pairs of stones. Unfortunately, it is unable to work at present due to bearing problems with one of the stones. We were, therefore, only able to see it in action on the excellent 12 minute video. The guide was well informed and humorous - as a result Chris Braithwaite said that we ought to be funnier!

Among useful and interesting things we saw at New Abbey were: control of the wheel speed from the milling area by means of a diverter (our "dump valve"); the complete drying kiln; the Heath-Robinson sack hoist; the side cheeks under the launder to prevent water spilling sideways out of the wheel.

Thanks to Sara for organising the trip and providing us with tea and cakes at Threave.

A pretty, and wet, flower
at Threave

Tuesday 13 September 2011

Good progress!

Ray and Richard examine the
finished flour chute
The flour chute is finished at last! Ray finally made the front covers, one of which is hinged for access to clean the inside. It will also allow the fall of flour to be seen - one of the issues with preparing the mill for milling is that all the interesting mechanical bits get covered up. We then sanded and cleaned the whole thing, sealed the inside joints with food grade silicon sealant, and applied some wood stain to the outside to prevent it looking too "new".

Richard carried on with making the parts for the damsel. This picture shows the top and bottom plates which will mount on the damsel shaft and carry the 4 bars making the eccentric to agitate the shoe.

The greenhouse window winder

Oak in the wrong place
After lunch we scrounged some nice mechanical bits from the window opening system in the old greenhouse, which has been demolished to make way for a fancy new one. The screw drive looks as if it would make a fine remote actuator for the gate valve, so the miller can control the water flow, and hence wheel speed, from within the mill.

Progress was held up a bit by the large oak branch that the gales had blown down on the path to the house.

Tuesday 6 September 2011

More fun with 3-dimensional geometry!

The flour chute, showing the rectangular side pieces
and tricky 3-D triangular spaces
Today Ray and Bob continued to work on the flour chute. Ray brought the final output tube which he had built at home, and we mounted that on its brackets. It then remained to build the side pieces to bridge the gap between that and the upper part that is built into the hurst frame. Unfortunately, the sides would have to be cut with angles in 3 dimensions, and even then it began to look as though they might have to be bent! After several cardboard templates and much head-scratching we went for coffee.

The coffee seems to have done the trick, as we then worked out that we could fit rectangular pieces to the sloping part of the chute, and make simpler triangular pieces to join them to the upper and lower parts.

The saw and the failed triangles

Ray's compound mitre saw managed to cut the first three triangular pieces, which have one edge at an angle other than 90 degrees to the flat surface as well as a 38 degree point angle. However, the fourth seemed to require a combination of angles and directions that the saw didn't want to accomodate. Finally, after many unsuccessful attempts, we made a jig to hold the wood at 45 degrees to the saw bed and finally glued the last piece in place.

All we need now is the front cover

Tuesday 30 August 2011

Continuing progress

Last week we dismantled the stone furniture over No 2 stone, the French burr. Today we cleaned inside and around the stone, hoovering up all the woodworking debris. We fixed triangular fillets of wood inside the base of the tun to fill the dead spaces alongside the vertical corner timbers where flour could accumulate undisturbed. Then we reassembled the tun and the stone furniture.
The picture shows a top view of the top of the tun, with the horse (the frame which carries the grain delivery system), and the shoe (down which the grain runs from the hopper to the hole above the stone). The cord which controls the angle of the shoe, and the ash spring which restores the shoe to position when jogged by the damsel can also be seen, though the cord joining the spring to the shoe is not visible. The damsel has not yet been fitted.

View of the stone furniture
showing the hopper refitted

We then refitted the hopper and covered the hole in the top of the tun to prevent dirt getting in. We also made further progress with the flour chute.

We are starting to plan for construction of a vermin-proof grain storage box. We also wondered whether we could adapt the sack hoist to give a mechanical advantage when used with manual power. At present it is useless as it has no means of connecting to the machinery, and therefore cannot use water power to lift material.

Yesterday, Bank Holiday Monday, we were visited by Duncan Hutt and his family. Duncan is currently a member of the North East Mills Group, but was formerly further West and took part in the restoration of our mill in the 1990s. In particular he recalled the construction of the launder - done in a very much of a rush to meet a deadline, and not surprising it needs re-building. He also noted that the people responsible for the major part of the restoration were building, rather than milling, experts. In any case, the mill was restored as a static exhibit. This confirms the view that we had formed on the basis that parts of the machine (bedstones, stone nuts etc) had been restored in a position in which they could not possibly work!

Tuesday 23 August 2011

We grind exceeding slow...

The shoe with magnet assembly
Another Tuesday and some more "finishing off" jobs, preparing for milling. We completed the magnet assembly intended to remove bits of metal from the grain before milling. The magnets are on a bracket that is adjustable for height above the shoe, from about 8mm to 20mm. The piece of plywood they are attached to is simply removed from its slot for cleaning.

We also took all the stone furniture apart again so that we could vacuum clean inside, add a few finishing touches, and stain the bits that haven't already been done. Ray is going to make some triangular fillets to fit beside the uprights in the base of the tun to avoid dead spaces that could trap flour.

Ray measures up for the flour chute

We also started to make the parts for the flour chute - some more complicated angles to cut!

On the trip last weekend we tried asking other millers about the SPAB instruction to paint all wooden parts that contact the flour with shellac. This was met with mirth and incredulity - basically, flour would scour it off in no time. No-one seems to do it, and no-one can see what is the health hazard of clean wood.

Saturday 20 August 2011

North West Mills Group Outing

The Eskdale drying floor

The stone and grain feed

Today Bob and Glenis, Richard and Sylvia joined about a dozen other members of the North West Mills Group in a visit to Eskdale Mill, Boot and Muncaster Mill. There was also a nice ride on La'al Ratty (The Ravenglass & Eskdale Railway) between the two mills.

The tentering at Eskdale mill

At Eskdale Dave King, the miller, very helpfully showed us round and described some of the amazing collection of antiquities on display - more a folk museum than just a mill! The mill technology seems truly ancient, for example, the tentering method being completely different from what we have at Acorn Bank. The stone bearing is supported on the centre of a large beam, which is supported at one end on the centre of another beam, one end of which is controlled by the tentering adjustment. The stone nut is driven directly from the pit wheel, there being no wallower or spur wheel.

The divided launder
This mill is open to the public and has its own website,
www.eskdalemill.co.uk/. Both the mills we visited have intact drying kiln floors, something of which we were very envious.
We were also interested in the way the water flow in the launder was split between the two wheels, as this was similar to the way we imagined it must have happened at Acorn Bank. This might become important if we ever get round to restoring our second wheel.

Richard inspects the bearings
at Muncaster
After a pleasant ride on the railway in the sunshine down to Muncaster, Bob and Christine Hoye-Turner, the owners of Muncaster Mill, made us very welcome. The mill is not normally open to the public these days, as it is their home, but they are prepared to show interested pre-booked groups round. I recall visiting it from the railway and buying flour 20-odd years ago. Bob is committed to not harming the historic mill machinery, but it was sad to see it lying idle, and one cannot help but worry for its future. Again we were shown round the mill, and were treated to a splendid spread of tea and cakes made by Christine.

By the time we got on the train back to Boot, it was raining so the journey was less pleasant! However, overall an interesting and enjoyable day - thanks to Margaret Croker who organised it on behalf of NWMG, to Dave King, and to the Hoye-Turners.

Tuesday 16 August 2011

Working on the details

Having done all the big construction jobs, progress appears to slow down while we complete the details that will enable us to mill for the first time.

The spring and cords attached to the shoe

Today we made and fixed a rigid metal pointer to indicate on the tentering rod how far the stones are separated. We made a spring from a thin piece of ash which pulls a string to return the shoe when the damsel pushes it. A cord holds the shoe at an adjustable angle to regulate flow. We have installed a shutter on the hopper outlet to control grain flow and Richard has made a neat screw control for it.

The hopper outlet shutter and screw control

We also began to make an adjustable carrier to hold magnets above the shoe to remove any bits of metal mixed in with the grain.

Tuesday 26 July 2011

This week's work

The horse and shoe

On Monday this week Ray and Richard made more progress on the grain feed, completing the woodwork of the hopper, including the slide shutter, and the shoe. Richard and Bob then made some steel brackets to support the hopper from a hoist while its best position was determined. Once we had sprayed these and fitted them, we offered the hopper up to the horse and left it in what we judge to be the best position.

Richard fits brackets to the hopper

We also discussed whether all the wooden parts that contact flour actually need to be coated with shellac as advised by the SPAB booklet, or whether there is some modern alternative. This needs further investigation.

Bob guides the hopper into position

Tuesday 19 July 2011

Weekly restoration work

Today Ray made further progress with the stone furniture. The horse is complete and the grain hopper is being constructed.

There is a snag here - the chamfer angle for the ends of the boards for an inverted pyramid is difficult to estimate. By trial and error we arrived at an angle of 36.5 degrees (the outer angle of the hopper being 60 degrees). I did manage to find a mathematical solution on the web (http://www.slyman.org ... PyramidAngleCalculator) which gives an answer of 35.3 degrees, but I guess we will go with what works.

Meanwhile, Bob and Richard were looking at the tentering for no 2 stones. This depends on a bracket fixed with a long bolt through the hurst frame, which is rather insubstantial at this point, due to woodworm and mortises from former use of the timbers. At present the tentering beam is supported by a car scissor jack. The bracket leans forward at a few degrees, but seems otherwise quite sound at the moment.
We decided to make a tapered washer out of 2 old iron wedges to compensate for the lean in the bracket, and keep an eye on the set-up for any deterioration.

Wednesday 6 July 2011

Visit to Lode Mill, Anglesey Abbey

Today we visited Lode Mill, part of the National Trust's Anglesey Abbey estate. This is another big, multi-storey mill, again mainly built of wood but with a large, iron 4 o'clock breastshot wheel.

The mill wheel

The stone floor

Once again we found the person in charge, in this case Chris Stimson, was generous with his time and knowledge and showed us round the mill and millwheel, including parts not normally open to the public.

He agreed with the thought that it was illogical to mill flour NOT for consumption. We would, however, have to sort out the lifting of delivered grain to the upper floor.

There was a suggestion that if you mill on four days or fewer in any five week period, there may be exemptions from some of the food hygiene regulations - but this may conflict with tea room use, of course.

Lode Mill also offers a hand quern and the opportunity to handle grain and flour - in general both mills had excellent educational facilities and interpretation.

Un-greased wooden cogs
Chris stated that you should NOT grease wooden cogs, as they pick up dust and debris to form an abrasive mixture that wears the wood too rapidly. maybe a better option for us would be to smooth the surface of the stone nuts.

Lining of grain boxes can be achieved with sheet aluminium as a Houghton, or metal gauze as at Lode. Other containers are mainly plastic Really Useful Boxes, one with a hole cut for the flour chute - on a table, not at floor level.

There are some issues around cleaning up after every milling, stone speed and tentering all of which we need to resolve - the input of a miller was stated to be essential, so Nic Jones' input needs to be obtained.

Tuesday 5 July 2011

Visit to Houghton Mill near Huntingdon

Today we (Bob and Glenis) visited the National Trust's watermill at Houghton. We were made extremely welcome by Phil O'Donohue and Steve (sorry, can't remember his surname), who spent two full hours showing us round and discussing some of the issues around milling.

Houghton Mill is a rather bigger affair than Acorn Bank, being on 5 floors and powered by a "4 o'clock breastshot" wheel about 15 feet in diameter and 16 feet wide. They produce flour in one operating session each Sunday afternoon, which is sold at the mill and makes a valuable addition to the economics of the property.

The main lesson was that if we are milling flour, we ought to sell it, otherwise the public will (rightly) ask why we are bothering. They suggested that we should get the local authority food hygiene people involved as soon as possible. Their flour is also used in their tearoom scones, and it was suggested we should consider doing the same.

They also have a hand and a rotary quern to show the concept of milling - I think we should have at least one of these.

The design of our tun needs some extra consideration, as the uprights will form pockets in which flour can become trapped. This photo shows the Houghton solution of fixing internal boards across the angles.

They always un-tenter the stones after each milling session, as the flour can pack down into a dense, cement-like substance if left under pressure.

Tuesday 28 June 2011

Further work on No 2 stone

Today we continued to work towards our goal of milling with the No 2 stone before the end of the season.

The tun is a two-decker structure, the upper section being detachable mainly to make it easier to get it in and out of the limited space.
Ray made good progress with the tun, putting in the cross bracing timbers which will support the top and help it to support the horse ...
... and built the top, made like the rest of the tun from tongue and groove floorboarding. All that remains is to finish trimming the edges of the top, cut the central hole for the grain to enter, finish the internal reinforcing, and finish and stain the wood.

Bob and Richard worked on the stone nut disengaging mechanism. The vertical bars have had to be modified as the holes in the tentering beam through which they pass are no longer vertical. To give a little flexibility, the bars are no longer fixed into holes in their bottom plate - instead they have collars which rest on the plate. Today's task was to fix the collars by drilling and fitting spring pins, and then refit the bars.

Finally we made a second hole in the cement dressing on the top of the runner stone and filled it with molten lead to balance the stone.