Southern Cross Farm Windmill


I quickly realised that in the summer the whole property is starved for water. There’s quite a bit of wind and this dries everything out very quickly and the ground, just below the surface becomes rock hard. Flowing water is available 24/7 from an old water-race built by convicts about 170 years ago. This was to carry water from the Plenty River to the Redlands Estate just up the road.

The trouble is that it is about 15 meters below the main level of land, down a hill.

I bought a little 2-stroke petrol pump for about $150 and this works admirably but obviously, it runs on petrol and has to be started.

I wanted something that runs automatically…. for free !

After not really much thought I decided that an old farm windmill would do the job. I could plumb it so that it watered the important spots automatically and best of all… every time the wind blew, it would do it for free ! 

Having made the decision the first problem was getting hold of one. I placed an ad in the Tasmanian Times and got one response from a farmer near Buckland who had an old Southern Cross head (gearbox), 10 ft fan and pump that he wanted to sell. We went for a look and $400 bought the lot. 

Next I had to get a tower and that proved a bit easier than I thought it would as it turned out a friend had three! (Yes, well, what friends don’t?)  A trip to Tunnack with the trailer and I had a Southern Cross one that I thought would suit. That was $300, and I was set. The hardest part was dismantling it and fitting the top half into the bottom and getting it on the trailer and back home.

And then the fun began….

I decided to put the windmill at the top of the hill remote from the water race which is about 70 meters away and 15 meters down. I knew that I couldn’t put the pump under the windmill as it was designed but decided to drive it by cable. At the time of writing this I have yet to complete that part and have been told by the owner of a windmill engineeering company in NSW that it can’t be done. If I do manage to do it then he wants first option on the patent! Right then…we’ll see won’t we…!

The site where the windmill is to be placed. Just out of sight on the left hand side is the main water tank for the irrigation system. On the trolley is the head and to the left a couple of segments of the fan.

 Having laid the tower out where it was to be erected I dug 2 of the holes for the support legs. These were 900 mm deep. I then made the 2 legs with a crosspiece on top for the tower to pivot on, concreted them into the holes, and then fabricated and welded on pivots. I added bolt on stub-legs, with the other half of the hinges, onto the windmill legs and joined it all together. 

It all sounds quick and easy but that all took a few weeks to do. 

The tower attached to the first two legs, raised slightly and supported by pallets. The 3rd leg has been attached and the hole for this has been dug. All that needs to be done to erect the tower is to pull it up, level it and concrete the third leg in.

Viewed from the other side the 3rd leg can be seen. the square bit on the end is to help anchor the leg in the concrete. I lifted it all this far using blocks and a small hydraulic jack.

Once the tower was ready to raise I built an ‘A’ Frame that also pivoted on the hinges. This is for supporting the rope (changing the angle of lift) to make it easier to lift up. Then with the help of a friend, Dave, and his 4wd we pulled it up and set the 3rd leg.

Pulling up the tower to set the 3rd leg. The ‘A’ Frame supports the rope to make it easier to pull up.

The base of the tower with the 3rd leg in the hole ready to be concreted in. I mixed all of the concrete by hand.

The tower up for the first time. Next it has to be dropped back down and the head, fan and tail added.

After concreting in the third leg I left it for a week to set really hard and then unbolted it and dropped it back down. This time I used my own car instead of calling on Dave again and it came down without a hitch. I then offered up the head assembly to the top of the tower and came across a pretty major problem – the head, fan and tail assembly were for a much bigger tower and the head wouldn’t sit properly on the tower! That made me think a bit!

The head offered up to the tower (above). The peak of the tower is hitting the top of the inside of the head legs.

In the image above you can see a leg of the tower going all the way up inside the head legs. it just can’t fit as it is.

After thinking about this for a while (I was getting good at that by this time) I figured out that if I put a piece of angle about a foot long on each of the tower legs at the top then the head should locate ok. 

One of the three lengths of angle to be welded to the tower legs.

The lengths of angle welded on and the head ready to be fitted.

I fitted the lengths of angle and the head went on beautifully. I then had to drill new bolt holes to secure the head. the problem with this is that the holes needed to be of a size suitable for fairly substantial bolts. I ended up using half inch High Tensile bolts, 4 for each leg.

Drilling the holes ended up being another problem and it wasn’t long before my hand drill began to complain. Anyone who has engineering experience knows that you need a pretty good drill for multiple holes of this size in steel and that was something I just didn’t have (couldn’t afford one either) so I took it as gently as possible. Four holes later and that was the end of that drill!

A quick trip to the local hardware store and I was carefully drilling holes again in an hour! (I say carefully because it wasn’t an industrial drill) The following morning the head was finally bolted on!

Then it was a couple of coats of paint to the head and start assembling the fan. (Another taxing thought session!)

First of all I laid out the fan on the ground. It came in segments so that bit wasn’t too difficult. One blade was missing and one was pretty damaged so I needed to have a couple made.

One of the blade segments.

The fan laid out on the ground, I repaired the distorted blade on the right and have removed the severely damaged one (separate on ground) At this point 2 blades are being made in Hobart.

Next I fitted the spokes to the hub. This is done by means of U-bolts and special locator blocks. then I started to fit the blade segments onto the spokes. 

Another problem…. because the head and tower weren’t designed for each other the blades hit the platform, which means it will have to be lowered.

 Starting to fit the blade segments onto the spokes. Because of the mis-match between the tower and head the blades fouled the platform so that will have to be relocated.

Another segment added. It was all getting rather heavy and lop-sided so I supported it all with pallets.

The completed fan.

The above 3 images show some of the stages of putting the fan together. I had no instructions at all for this and it really taxed my brain. The hardest part was not actually assembling it, but bolting it all together. Everything is pretty much under a fair amount of tension and the last few bolts were the worst to get in and tighten.

One of the many good rules I have worked under in my fairly long engineering career is to never buy or use cheap tools and this certainly was proved several times during this project. One time was with the hand drill and drilling the holes to bolt the head onto the tower and another was while I was bolting the fan together…

In the picture above you can see the spokes from the center hub to the outer rim. These spokes hold everything in place on the hub. At the end of each spoke is a thread that a nut screws onto to keep it all in place and under tension.

Some of these threads were damaged and needed re-cutting. The windmill is pretty old and so it was an old engineering thread called ‘Whitworth”. 9/16″ Whitworth to be exact which is no longer used. Pretty much everything now is Metric (as opposed to Imperial which most of the old threads are generically called)

The tool for doing this is called a ‘die’. ( Conversly the tool for cutting the thread inside a hole is called a ‘tap’ ) 

I have a fair amount of taps and dies but didn’t have this one so I had to buy one. Then I found that I couldn’t buy nuts of this size without a lot of running around. Nothing is ever easy is it!

Luckily the 9/16 Whitworth thread is almost the same as another Imperial thread, 9/16 UNC (Unified National Coarse) and most of those sizes are readily available, so I thought that I’d just re-cut the thread to that.

Still didn’t have a die of that size though….

I rang a local engineering supply company and they had one for $22, but it was in a branch at the other end of the state, a couple of days away. I wanted it now (as you do) so I went to one of the big hardware chain outlets.

They had a complete set for $62.00. I was a bit dubious about it as a set for that price (about 25 taps and dies) is a bit different from a proper “Sutton” engineering one at $22.

Anyway, I really needed that 9/16 UNC die so I bought the set.

I got it home and tried the die from the set only to find it completely useless. It started on the thread ok but as soon as the thread got tight it wouldn’t cut and just jammed. Bloody hopeless!!

So I ordered the professional engineering one from the engineering supply place and had to wait for it to arrive.

It worked beautifully when I used it!

Before I finished assembling the fan I had to lower the platform as it was in the way of the blades. This just involved grinding off the heads of the old bolts so I could take off the wooden pieces, which I discarded. I then unbolted the supports and moved them about 8 inches lower by drilling the holes and bolting them on.

I then bolted on new wooden platform boards, and it was done.

The lowered platform supports. You can see where they used to be by the black marks further up the tower.

Once the new platform was on I had to lift it all up so that the centre of the fan was at about head height and the fan was vertical. This was so I could put the tail on. This is the part that turns that windmill and makes sure that it faces into the wind.

The tail also has what’s known as a ‘reefing’ mechanism incorporated. This is so that the windmill can be turned away from the oncoming wind. (during periods of very high wind, maintenance etc) Basically it turns the tail 90 degrees so that it parallels the fan. This is done by a wire from the tail assembly to a lever at the base of the tower.

When the lever is pulled, the wire operates another lever at the top of the tower that raises a collett on the center-piece where the tail is supported which turns the tail. Very simple but pretty clever.

The whole thing raised ready to put the tail on. I’ve said it before but it’s amazing what you can do with a small jack, a crowbar and some blocks.

 The tail. I’ve not had a lot of dealings with windmills like this but I’ve never seen one that hasn’t got bullet holes in the tail. This one has a few!

 The bullet holes in the tail.

 

The fitted tail. The metal rod next to the gearbox and the horseshoe shaped part between the gearbox and the platform are part of the reefing mechanism. The new platform can also be seen.

 Looking at it from the other direction.

At Last! Ready to go! Finally got it ready as it was getting dark one night. The moon can be seen to the left of the fan.

The next job was the one I had been waiting months to do…. and that was to pull it all up to the vertical – without any mishaps of course!

I thought it best to use a vehicle with a winch this time in order to have more control over what was going on. A good friend, Bob had a Mitsubishi Pajero at the time and that had a winch on it. 

Bob offered to do it so along he came the following Sunday morning and we hitched up. Dave came as well and it went up without a hitch! I’ve got to admit though that I was nervous to the point of forgetting to take many photos and the one below is the only one I have of the exercise. It was quite a relief in the end to see it standing there!

The only problem we had was very minor and this was a slight misalignment of the third leg with the foot concreted into the ground. We put this down to some extra welding I had done to the base frame to brace and strengthen it a bit more. That was soon fixed though.

 Bob’s Pajero hitched up and ready to winch. It bounced about a bit on the way up but that didn’t seem to affect it too much.

Here it is a few days later! I took the rainbow to be a great omen!

All I wanted to see now was it turning in the wind. There is a really good website called ‘The Back Shed’ (http://www.thebackshed.com/Windmill/home.asp) that focuses on windmills and home power, stuff like that and on their home page is a section that says:-

“There will be absolutely no wind for several days after you have built your first windmill!”

How true this is!

It took 4 days for the wind to blow so I could see it spinning!

The next step in this project is to connect up the pump and to start moving water. Normally this would be quite an easy task but not so in this case as I am going to have to cable-drive the pump. I’ve been told that it cannot be done so that hs made me all the more determined.

That s going to be on another page though, this one has got too long! Thanks for looking.