MadModder
Gallery, Projects and General => Project Logs => Topic started by: smiffy on November 03, 2018, 06:08:46 PM
-
For nearly a year I have been restoring a 1790 water mill that belongs to a friend . This is a 2 stone mill driven by a undershot wheel .
There is also a turbine which I have reinstated
All the work is being done single handed so progress is fairly slow and as this is a private project funds are limited.
The pictures here are of the francis turbine which has a 24 inch runner and works at a head of 5 feet .
All the bearings are lignum vitea and I have used all the original ones as new lignum vitea is almost unobtainable
My objective is to be able to produce flour some time next year
-
Where are you in the world?
A location might well produce volunteers, cash, or lignum vitae bowls (bowling green type) that might do for replacement bearings.
I would volunteer if you are not too far away from Wem, Shropshire.
-
There's a gent supplying lignum vitae bearings for engineering applications, and growing the next generation... ran across it in the ASME magazine a few years ago.
Sent from my SAMSUNG-SM-G891A using Tapatalk
-
A few more pictures of the francis turbine . The first thing was to split the drive shaft and remove the coupling then remove the thrust pad and thrust bearing that is a block of lignum vitae
Then I removed the spider which controls the opening of the vanes . This took some considerable time as everything was seized solid .
Then it was possible to remove the top plate and expose the vanes and central runner .
The years of water running through it had formed very hard limestone scale that made dismantling very difficult .
Thanks for the idea of using bowling balls but unfortunately they are way too small as the main thrust bearing would require a cubic foot which would be available but at great cost
-
That's some proper old school engineering there! What are the cups made of in the turbine, they look like cast iron - if so, that would be absolute cutting edge technology for 1790?
-
The turbine was installed in 1907 to to power a generator to provide electricity to a local house for a set number of hours each week . There were also 2 electric bread ovens installed in the mill . Unfortunately both generator and ovens are long gone .
Before the turbine was installed there had been a small undershot wheel driving one set of stones .
At the other end of the mill is the larger wheel driving 2 sets of stones .
The turbine runner is the most fantastic casting , all the other runners I have seen have pressed steel buckets but this is all one casting.
The other pictures show the bearing housing which sits on top of the spider frame . The whole weight of the shaft and runner is carried on the wooden thrust bearing This housing also houses 3 radial bearings The reason why the turbine stopped working is probably because this housing was broken .
I repaired it with strong backs to secure the 3 radial bearing
The original bearing retaining plates had been held in by 4 3/8 bolts on each of the bearings . these had all sheared and the whole assembly tied together with a thin steel strap
The other photo is of the operating gear . This turns the spider to open or shut the input vanes The original was missing so I cut the ew gear out of 15 mm plate a welded 3 pieces together
-
Smiffy,
Maybe the bearings could be made in this fashion, rather than a solid sizeable lump of LV?
https://lignumvitaesolutions.com/products/marine/stern-tube-bearings/
-
Hi Smiffy,
I'm really enjoying seeing the progress on the mill :clap:
From what I can see in the photo of the turbine wheel, the end of the shaft (bottom end?)
looks to be worn down to approx half its original size?
If there was that much play in the rotating shaft and wheel was there any contact wear between the turbine
blades and housing?
The inlet guide vane mechanism design is very similar in principal to the Gas turbines I worked on !!
John
-
The spigot on the end of the rotor shaft is not a bearing ,it locates in light cast iron cross piece in the output tube and once the main bearings are set it should not make contact with anything . I have not got any pictures of the support cross piece as it was always under water
At some time the bearings had got out of order and that is possible when the shaft became worn
As I have mentioned before the main shaft is supported on 1 main thrust bearing and 3 radial bears on the turbine .
The main shaft is 2 pieces of 3 inch sold bar joined in the middle . The top of the shaft is supported in a plain bronze pillow block bearing
The photos show the bearing housing and the retaining plate which had come adrift because the bolt had sheared.
I have also started to make a new gear to replace the cast bevel gear which is called a wallower
To make the gear I am going to fabricate it and started by making the teeth by sawing at 30 degrees 5 inch lengths of 45 mm x 45 mm
solid bar I did it in my old power hacksaw as it gave a better finish than my friends all singing and dancing cnc band saw
It took 10 hours to cut 44 teeth
-
Started work on the new gear , the original is all 25mm thick cast iron . I could have made the new gear from steel of the same thickness but on refection that would be overkill and the cost of 25mm is a bit pricey ,plus bending it is more than I can handle .
So I settled on making the whole thing from 12 mm plate mainly because I had a 2 x 1 meter sheet to hand
Profiled out the main hex section on a cnc machine and folded a piece of 130 x 12 mm plate into a hex to make the center section tomorrow I shall weld it together
Then I will have to roll a cone at a 20 drg angle to weld the teeth to , That could be a bit of a problem as I have not formulated a plan of action yet
I might do it in 2 sections in my press
-
This is the gear that I am replacing .It is driven from the pit gear on the main wheel and drives the vertical wooden shaft .
This shaft has a large cast iron gear on it with wooden teeth that drive the mill stones
The gear is held onto the hexagonal wooden shaft with wooden wedges
-
Very nice bit of bending - and it fits :thumbup:
-
Thank you, not sure if it was luck or judgement ,possible a bit of both
Mike
-
Years of experience I suspect :clap:
-
I believe that those inserted wooden gear teeth were often/usually made of apple wood.
-
Traditionally the teeth are supposed to be made of apple or pear wood but in reality they were made out of what hardwood was available, Horn beam is a good alternative along with elm
Welded up the first part of the gear today , tomorrow will get it welded up and start making the cone .
Mike
-
Hi Mike,
Great to see the work progressing :clap:
One small point though, I can see eight sides in what you described as a hexagon :Doh:
:scratch:
John
-
My mistake should have been octagon
Nice to know that someone is reading my ramblings and paying attention
Mike
-
Started making the outer cone for the bevel gear Decided to use 8mm plate bending anything thicker becomes a bit of a issue.
Originally I was going to use plate of the same thickness of the casting . I decided that this was a bit overkill and went for the steel sizes that I had in stock and could easily handle . Making the cone in 4 pieces as I could cut the shape required from a piece of 180mm x 8 mm .
Cut pieces of plate to match the radius of the cone and formed them in the bender .
Clamped it up and with a bit of help from some clamps and the No 1 persuader a 28 lbs sledge hammer 2 of the sections are finished
Should be able to finish it tomorrow and start welding the teeth on
Mike
-
Can you buy that tooth shaped steel, or are you milling it up? That is a superb bit of fabbing!
-
Hi Mike,
It looks like you are well equipped to persuade steel into shape and keep it there with those serious looking clamps :clap: :clap:
John
-
The teeth are cut from 45 x 45 steel bar . The angle is 30 degrees one side and 90 the other
This is a singe direction gear so only the 30 degree needs any attention
As I described in post 8 I cut the gears in a donkey saw
When this is all made and fitted against the pit gear i might have to shape the teeth with a angle grinder , it will depend on how the teeth have worn but it cant be any worse than the one that I am replacing as it was jumping out of mesh due to missing teeth
Photo is the pit gear I will take some better photos this week
-
Right, gotcha, are you getting two teeth out of one cut?
-
Yes 2 teeth per piece but still had to cut over 2 meters of bar . Unfortunately the 45 sq was the only material I did not have and had to buy a 6 meter length . That was a big lump to handle
Apart from consumables ,mig gas and wire etc this is all I have had to buy .
By the time I have finished I will have used about 15 kgs of mig wire and 150 kgs of steel
Only money spent £80 on the 45 sq bar and about 30 hours workshop time A bit different from the £3000 to £4000 quote for a new casting
-
Finished the last piece of the cone . The easiest way I find to measure a curved distance is to use a traveller . Blacksmiths and wheel wrights would use this tool to calculate the distance around a wheel and transfer the measurement to a tyre so it could be made to the correct size . I used it to measure the last piece of cone so that I cut the right length
A traveller is a disc with a center pivot held in a frame , A chalk mark is made on the the wheel were it touches the object to be measured .Count the revolutions and mark the part revolution with a second chalk mark
Transfer this measurement to the piece of metal to be cut . I know most of you will know of this means of transferring measurements but it surprises me how many people do not .
The other photo is just a small selection of G clamps . I dont use them very often now but when you need them they are invaluable .
I often wonder what will happen to all my tools when I no longer need them . The amount of younger people interested in getting involved in this type of work seems to be very small
-
I took the gear to the mill today to measure it up for fitting and against the old gear
Also took the chance to get some photos of the stones and drive gear
We have had quiet a lot of rain over the last few days and the weir has plenty of water
I will weld the teeth onto the gear tomorrow and hopefully get it mounted later this week
It is called a wallower gear as it is difficult to get it running square in both directions and it wallows about as it turns
I will have to lift and turn the stones over to dress them , They are french burr stones set in plaster of paris
After the stones are dressed flat and the groves are recut they have to be balanced and leveled so that the gap is equal all around between the 2 stones .
This is done by placing lead weights in pockets on the top of the stones The last picture shows the lead weights
The bottom stone is stationary and the top stone turns . I will get some pictures of how it is adjusted at my next visit
Mike
-
After giving it some thought and coming up with all sorts of impractical solutions I decided that the easiest way would be to work out the circumference and divide by the no of teeth.
This sounds easy enough but in practice it takes a bit of juggling . The distance between the teeth was 56.81 mm and after a couple of attempts at the marking out I tacked the teeth on . Final tolerance is + or - a gnats kneecap,
Tomorrow I will finish the welding
At last it is starting to look something like its supposed to.
Mike
-
Now if that was me, half those teeth would have been welded the wrong way round :bang:
-
Now if that was me, half those teeth would have been welded the wrong way round :bang:
I know exactly were you are coming from .I just hope I have them facing the right way
Mike
-
A bit delayed but finished welding the gear today . Hopefully will have a trial fitting next week \
-
You're a braver man than I am.
I would have just left the teeth tacked on until after the trial fitting.
Don
-
I had 1 more job to do before taking the gear to the mill to fit . I drilled a hole in each of the 8 sections to allow water to escape as every few years the mill floods, some times to a depth of several feet .
I keep the slugs from the holes as they are easy to turn into thick washers Always believe in waste not want not
Mike
-
I am in awe.
How do You get the info/skills on what needs to be done ?
As for bearings ..
the igus engineered plastic would probably be excellent, cheap, and they might comp You.
If You want, I could ask them.
-
The proof of the pudding is in the eating .as the saying goes so with no more ado loaded the gear up and went to the mill
First photo shows how worn the original gear was . the next are of fitting it up The original horizontal axle tree shaft is long gone and has been replaced with a 9 inch square solid cast iron shaft .
When this was done the center of the water wheel was reduced to 9 inches but the pit gear was replaced as this has a 9 inch square hole from new . I think this was carried out in about 1850 as far as i can ascertain.
It is very difficult to get details about work carried out and when as so little was recorded
I know that in 1980 the wheel ,stone work and sluice gate was rebuilt . They never went any further either due to lack of funds or interest.
Over the next week I will finish fitting the gear and to get a correct mesh I need to realine the wheel shaft . I will need to move the whole wheel, shaft and gear out about 40mm . This will not be a problem as the plummer block bearings have never been bolted down .
-
The shaft is supported on a steel shaft fitted into the end of the axle tree shaft This sits in a bronze bearing which is held in a cast iron block with 4 adjustment screws This is completely worn out . I have some suitable bronze but not a lump big enough so will make a steel housing with a replaceable insert
The wheel shaft bearings are ok Mike
-
Mike the bronze bearing block looks very brassy - perhaps they did it the cheap way before :clap:
-
Yes Andrew I agree from the photo but in real life it looks more like bronze but anyway its run out of newness . This bearing takes a fair amount of pressure so would welcome ideas on using a modern bearing
Mike
-
Does the bronze block take the end load of the steel shaft too, or just the side to side loads?
Don
-
Yes both radial and thrust Total shaft weight is about 1 ton I will probably replace like for like as that bearing will have done 50 years of running .so the design has stood the test of time and all the other mills I know have the same design Mike
-
I realigning the water wheel shaft by pushing it over with a 20 ton hydraulic ram until the gear mesh was correct from the pit wheel to spur wheel .
The next gear on the vertical shaft drives 2 diagonally opposed gears that drive the stones which are directly above them .
Its important that the meshing of both of these gears is correct
As the bearing block that I posted a photo of yesterday wears the main gear will drop . Over the life of the bearing this is about 3 inches . This will cause the stones drive gears to come out of mesh
To compensate for this the gears are adjustable on there shafts.
The drive shafts are square and onto this is mounted a casting with a square hole in it which is a sliding fit onto the shaft
The out side of this casting is a tapered square which fits into a tapered square hole in the stone drive gear . The outer piece is held at the correct height by 2 pieces of wood which are bolted to the inner shaft .
All that is needed to do is saw a equal amount of each piece of wood and the gear will drop down on its square.
Its not possible to alter the mesh by moving the drive shaft itself as this would alter the clearance between the grind stones which is critical to the correct operation of the mill
The top stone is mounted directly onto the shaft
If it is required to take one of the stone out of used the gear is simply lifted of the tapered square and tied up out of the way.
This probably sounds a lot more complicated than it is in practice . Sometimes it is not easy to describe a simple design
The next major step will Get the top floor cleaned up and the sack hoist working
Photos show the stone drive gear and the correct mesh , jacking the main shaft and the top floor and sack hoist
Mike
-
I carried on with getting the shafts into order The vertical shaft was still a bit out of line which I did not realise until I came to replace the floor boards. I moved it until the gap was even ,
The main wheel shaft has proved a bit of pain . The wheel runs in a bearing block on each side and the pit wheel runs in 1 bearing with a coupling to the the wheel part .
This coupling is made of 2 flanges bolted together with a squared hole in each to accommodate the shafts . the square on the pit side has worn badly and the shaft is a slack fit in the hole This makes it very difficult to work out when its in the correct position.
This is a crude form of uj so I need to leave some movement in it.
This is not something which is easy to push about as it weights several tons and every movement requires the jacks to be moved to a different position
Although there looks to be plenty of room to move about the space is actually quite restricted.
I was going to run the wheel and let it settle in to a position where it was happy but the water is very high today which causes problems.
The weir was up by about 18 inches but the down stream water level was up by over 3 feet . This always happens after short periods of heavy rain due to restriction about 3 miles down stream. This means that the tail race is backed up and the water can not get away from the paddles .
There is also a grid above the sluice gate to stop large pieces of wood getting stuck in the sluice gate or wheel . This has become blocked and is restricting water to the wheel .
I just did not fancy putting my waders on a getting into 5 feet of fast flowing water to clear it.
Hopefully in a day or 2 the level will have dropped a bit
Photos show the Level of water , The main shaft coupling and the vertical shaft with floor boards refitted
-
.......
The weir was up by about 18 inches but the down stream water level was up by over 3 feet . This always happens after short periods of heavy rain due to restriction about 3 miles down stream. This means that the tail race is backed up and the water can not get away from the paddles ...........
Hi Smiffy,
We see the same effect on the weir at our hydroelectric system on the River Goyt (twin Archimedes screws). I was surprised that something 3 miles downstream would cause a problem. I'll try to have a walk down our river to see if there are any areas where we could perhaps do something to improve the flow. Unfortunately there isn't access via footpaths the whole way down so I may have to don my waders and paddle.
I'm in awe of what you're doing with the mill!
Cheers.
Phil.
-
Smiffy,
This is truly a bonkers project - I'm absolutely loving it, and you've done some really cool work there. :clap: :clap:
:nrocks:
Can't wait to see the video of it all up and running as it would have been in the 1700s :thumbup:
-
Thanks for your comments . The restrictions down steam are several tributaries joining and road bridges so not munch i can do about
that . Today I followed it for about 20 miles and the whole river down to where it joins the Severn is about 3 feet up . It does go down fairly quickly so if we do not get any more rain by tomorrow the down steam levels should be quiet a lot lower
Ade thanks for your words of encouragement .
The people who should take the praise are the original builders The quality of there work amazes me and they did it without any power tools .
To understand the effort required some years ago with a few other like minded people we set to to build a traditional timber building along the same lines as the traditional black and white houses that are a feature of our county side
This entailed starting with green oak as felled of about 14 =20 inches in diameter and 15 - 20 feet long and turning it into straight square timber This could either be used as it was for principle posts or cut on a pit saw into suitable size timber for studs etc .
Every thing had to be done traditionally with no use of modern power tools
The round timber is squared using a 7 lbs felling axe and a side axe . Every piece of timber produced before power saws was done using these 2 tools
The method of doing this is 1 Place the tree on 2 other trees at 90 degrees to get it off the ground and orientate it so the the place that you want to start with is vertical
2. Mark 2 vertical lies on each end using a wooden set square and plumb line [no spirit level allowed]
Join the top of each vertical line along the length of the tree and mark with a string line
3 Standing on top of the tree using the felling axe cut a series of birds mouths to the depth of the string line mark
4 still standing on top of the tree and in line with it knock of the blocks between the birds mouths , this should leave a rough but straight vertically flat side to the tree
5 Using a side axe and standing on the ground and using the axe vertically you can produce a very flat and straight piece of wood
6 Repeat for the other 3 sides
The adze is never used despite what many people think. its a tool used for shaping curved surfaces and rarely used in this type of work
Photos show all the tools required for basic framing felling axe ,side axe mortise chisel and 2 bruzzes which are square chisels used to finish mortise corners
This how the vertical axle shaft was cut and it is totally parallel a credit to the men who made it Mike
-
Your are out of luck if you are left handed .
-
Rules me out then being cack handed :clap:
-
Snap us lefty's note is things like that .
-
Your are out of luck if you are left handed .
Afraid not you can get both left and right handed They are available but from here as a special order https://www.gransforsbruk.com/en/product/gransfors-broad-axe-model-1900/ Mike
-
Photos of timber hewing in no particular order but shows whats involved . I think that its important to understand how something was made before you can begin to understand how to restore it .
The next thing I need to try my hand at is stone masonry Mike