Spinning and other metal work

There are some awesome 19th century metal working workshops at Sovereign Hill.  Next week, I will be visiting one that is 150 years into the future from these workshops, but more on that at the time.

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One of the things I did want to see while I was there, was the metal spinning.  While it is a really old process, it is still very much in use today, forming things like metal bowls.  Of course technology has made things easier, but you would have to be impressed with the quality of the result from the old techniques.

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The process here involves holding a flat disc of metal against a mold.

SH-8The metal worker has a long rod that is supported against the upper arm, and against a pivot point close to the disc.

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By then gently pushing selectively over the surface while the mold and disc are spun rapidly, the metal is slowly bent in until it is flush against the mold, copying its shape.

I found it really interesting that as the metal was being spun, it actually curved outwards as the metal spinning stretched the metal.  It was then rolled over towards the mold with the rod.  This process was repeated as the metal continued to be stretched and molded to shape.

SH-6I wanted to get more background about the process, especially the traditional aspects of it, but the gentleman demonstrating made very clear he wasn’t interested in sharing.  A shame, seeing as he has been doing it for about 50 years apparently, and would have a wealth of knowledge.  He’d also have shoulders of rock doing this for so long.

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Think some areas of the workshop haven’t been cleaned in those 50 years either!

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The workshop produces many of the items for sale at Sovereign Hill – bells, plates, gold panning pans etc.  Bought one of those as well – cost all of $12 too.

Spun items (produced by hand, or by modern methods) have a distinctive fine ribbed surface.  Next time you come across a metal bowl, have a look and see if you can work out if it was produced by spinning, or some other process.

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Episode 117 Traditional Carriage Wheel Production

Wheel Steel

By far and away, my favourite area of Sovereign Hill is the wheelwright’s shop.  This is a fully functional 1880s/1890s industrial revolution vintage workshop, full of line shaft driven machinery, and some really cool specialist machines at that.

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Powerhouse

Machines need power.  It can be horsepower (literally), water power (waterwheel), but what really rocked the industrial world was steam.  I mean really rocked the world – it was (and still is) an incredible way to transfer energy from fuel to a mechanical form.  Not 20 years ago, I was still working on a steam powered warship (which used the more traditional method of flame in a boiler), but even today, nuclear power is still fundamentally a steam system, just with a different source of heat.

Sovereign Hill has wood powered boilers to drive the place.  They run at a pretty minimal level compared to how much demand there would have been with the place rocking “full steam” at the end of the 19th century, but they still go through an entire tree a day (and no, I don’t see that as particularly wasteful, or even a lot in any respect).

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The steam produced here is saturated steam, so it is not particularly high temperature or pressure, but is still more than enough to drive the steam engines around the place.

SH-83In the wheelwright workshop, the engine sits in one corner, and drives a really significant pulley and belt.  This is then distributed by a series of shafts, pulleys and belts to the various areas of the workshop.

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Creating the hub

First step, after choosing a suitable round of timber, and knocking the bark off, is to drill the central hole.  Once, this would have been done by hand with an auger bit…..

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…. but a boring machine turns a difficult and tedious task into something a whole lot easier, and faster.

The timber is processed green, very green, so it machines really easily.  It does mean that there is a long drying time involved in the process, but more on that later.  When you watch the video, look at just how much moisture pours out of the hole as it is drilled through, and in a number of steps, the amount of steam coming off the timber as it heats up from being worked.

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The drill bit doesn’t exactly look as you’d expect, but it is the shape that works best in drilling with the grain, deeply through the core of a log that is very wet/green.

The wheel on the right moves the log back and forward, plunging it into the drill deeper and deeper each time, until it pierces through to the other side.  The operator has to back off very frequently to clear the shavings.

A square-ended shaft is rammed into this hole, for mounting in the next machine – the hub lathe.

SH-81This has two cutting sides.  The right hand side planes the hub down to the correct diameter, then the blades on the left are bought to bear to shape the ends, and gently radius the hub along its length.

With the wood being so green, the timber peels off in a sheet, in quite spectacular fashion.  Easy to imagine this is not dissimilar to how ply is made.

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The hub then moves over to the mortising machine.  There are a couple of steps that this machine does.  The first is where it drills holes around the circumference, which allows the morticing chisels to work with a lot less effort.

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The second step involves the morticing chisels that cut with quite a punching action – very violent, but also very controlled.

The machine automatically raises as lowers the hub into the chisels via a large cam on the front, and indexes from one hole to the next via a auto-advancing mechanism on the left.  It is really impressive!

SH-30The hub is then shelved.  For years.

Like any other timber, a basic rule of thumb is a year for every inch of thickness for it to dry.  2-3 years for the average hub, up to 10-15 years for really heavy hubs (for really serious wheels!)

I don’t have any photos of the spoke manufacture, but you can see more in the video anyway.

The lathe creates the oval spoke, with a square end.  Next, a quick pass through a tenon former creates the initial shoulders, that will then be refined once the spoke has been seasoned.

The third machine shaves a small amount off the circumference of the spoke, near the hub end.  This is a deliberate weak spot, that allows the spoke to flex and absorb vibration, not unlike the narrow portion of a hammer handle.  A spoke only takes a few minutes to make with this method, saving hours of work with planes, saws and spoke shaves.

Once the spokes and hub have seasoned, it is remachined to final dimension (after all, there is quite a bit of timber movement during drying), and then assembled.  The spokes are hammered home, in every second hole, creating the wheel spider.  It is obvious where this name came from.  The spider is assembled in this way, other the increasing buildup of forces in the hub from each spoke would cause it to explode apart by about half-way around.  The spokes are not secured in by any method, other than friction.

SH-28Round tenons are cut on the outside edge with another machine.  This is pretty manual, but looks easy and quick to operate.

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If the workshop has a quality supply of good timber, and the required equipment, the rim timber can be steam-bent in to half, or quarter rounds.

SH-73 SH-74This is a great technique, as it ends up with very strong members, that have the grain running around the rim.

However, if the timber supply is limited or steam bending is not available, much shorter sections can be used that tie two spokes together, and this is repeated around the circumference.

These are called felloes, and are typically cut out on a bandsaw.  They are held against the spokes, and the locations marked, then drilled.  Getting the felloe attached to the spokes is a bit tricky, given they are drilled for their final location, up against the shoulder of the tenon rather than the larger diameter of the end of the tenon.

To fit these on then, another tool is needed to pull the spokes apart so they can engage the holes, before being driven home.

SH-27The gap between each felloe is quite small, but even so, a tenon saw is used to cut in between the gap to ensure the joint can close up fully.

The steel tyre is the final part, and this gives the wheel its real strength.

In an older process, the steel tyre is cut shorter than is needed.  This is calculated as a combination of the size of each gap between felloes, and a fudge factor that comes from the experience of the wheel wright.  A metal bender is used to bend the steel into the required diameter hoop, and the ends are then forge-welded together.

SH-88I am not sure what the pile of hoops outside the workshop is for – tyres are normally cut to match to the individual wheel, not in bulk.

With the undersized tyre, the next step is to get it to fit on the wheel.  This is done by heating to a black heat in a fire, which increases the diameter of the metal hoop, sufficient to be able to fit over the wheel.

The wheel is placed in a pit with shallow walls, surrounded by barrels of water.  The tyre is dropped over the outside of the wheel, and before it has a chance to cause the rim to start to burn, the barrels of water are kicked over, flooding the wheel and cooling the rim.  If the rim had burned, it would have resulted in a layer of carbon, and a great opportunity for the steel tyre to slip off the rim.

SH-26You can see an example of a pit behind these carriage wheels.

Some wheels are designed to have a bit of curvature – this provides additional capability of the wheel to flex, which also takes some of the forces that the wheel will encounter in use.

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Sovereign Hill has a rim press to fit tyres a lot easier than the fire-method.  These are more for wheels that are aesthetic (cosmetic), rather than functional.  The tyre is larger than the diameter of the rim, and the rim press compresses the tyre onto the rim.

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They have had fun with this press, including trying to see what would happen if they kept going and going.  Not surprisingly, the wheel failed, which each spoke snapping at the weakest point.

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So that is the story of carriage wheel manufacture at Sovereign Hill, or at least as much as I was able to absorb from watching their demonstration.  The associated video is in the next post, and it is as good as I could get, shooting handheld in the middle of a large crowd of jostling people.

Following that, I’ll put up another post, showing a certain 4′ carriage wheel that I purchased from the place, made with all the traditional techniques.

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There’s gold in them thar hills

Click here to view 3D model of Sovereign Hill

Click here to download Google Earth

After the alluvial gold became more scarce, gold prospectors dug into the earth to continue to find the riches that were available around the Ballarat area.

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The mines were either relatively shallow, dug by individual prospectors, or ran deep, supported by more elaborate mining setups by larger companies, that then employed miners who then drew a wage to dig, rather than earning nothing, or everything.  These miners earned around $65000 in today’s dollars, but the work was dangerous, and their life expectancy short.

If not for the cave-ins, drowning and all the other heavy risks, the air itself was laden with dust, and every breath took a toll.

Just out of interest, the mine above was dug into ancient creek beds, and yielded a 69kg monster.  At today’s price, you would get just about enough change from $3.5 million to buy a cup of coffee (but it might have to be instant).

Gold-10 Gold-12Larger mines may have been built stronger, but the miners constantly listened to every murmur, every creak, and when the timber started to talk, it was time to run and even then, it was often too late.

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Gold-9Cartload after cartload of quartz was removed back to the surface for processing.

If you were exceptionally lucky, the gold was there to find.

Gold-11The quartz taken to the surface was then processed to find what gold was trapped inside.

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This could be broken up by hand (sledgehammer), but to process the amount being mined, more elaborate methods were introduced.

One such example is shown above, using a method not dissimilar to milling wheat into flour, this crushes the quartz with a heavy, iron-reinforced stone wheel, pulled by horse.

Other subtle methods were used later in the piece, such as a ball grinder that uses a bowl with a free-running large stone ball to grind the fine samples even further to release the gold therein.

With the increasing introduction of industrial methods to increase yield and process the maximum amount possible, we have the crusher!

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Rock is fed in from the right, and hammers pound it to dust, before it flows over an oscillating cloth bed designed to catch the gold, while the quartz dust flows over the top to discard (or finer sorters).

But I don’t think you get the full effect in a photo or two.  So this might help understand just how much force is really involved!

Once the gold is extracted, it is melted down to have its impurities removed, and cast into ingots.

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This fiery brick is $150000 of pure gold.

Line Shaft Live

Probably the thing that I enjoy seeing more than anything else at Sovereign Hill, are all the line shaft driven machinery.  I’d love to have a workshop straight out of the 1890s.  I’d feel right at home.

This is one of the many working workshops at Sovereign Hill, powered by steam, and line shafts.

Shot by my daughter on an iPhone (without any encouragement from me – something starting to rub off?!! :) )

 

Xmas in July, part 1

Took the family to Sovereign Hill for their Xmas in July that Sovereign Hill runs each year, and had an excellent time.  Not only what they have done for the occasion, but more broadly because I really like the whole Sovereign Hill experience.

Sovereign Hill, for those that don’t know, is an open-air museum and historical park, situated in an early gold diggings area in the Ballarat region.  It covers the time around 1850 (with some of the equipment being closer to 1880s/1890s as the industrial revolution found Australia).

 

These are just the outside of some of the buildings, but what is inside is the real treasure.  Being the mid 1800’s, wood and steel are the main materials of fabrication, mixed with a huge amount of ingenuity.  Not to mention, nothing was made with a designed life expectancy – a tool was made as well as was possible, and that means many of the tools are still very functional today.  There are mines to explore, gold to pan for, 9 pin wooden bowling etc etc.

We stayed in the attached accommodation, so had our own access pass through one of the buildings into the site, which was a very nice feature.  Being able to take in the place in as big or as small a bite as you wanted, being able to return for a rest before the next assault made for a really enjoyable experience.

The Xmas in July was well done too, and the weather in Ballarat lived up to its reputation – cold!  Which was very appropriate for a winter-wonderland based Christmas experience (complete with simulated snow (of the soap/foam variety), which was very much for look than tactile experience!)

At night, the buildings were illuminated by the same company that does other building illumination projects, including the Sydney Opera House, and White Nights in Melbourne.

We attended both the Xmas-type functions (such as the building illumination, and their Xmas dinner), as well as the standard offerings, such as the exceptionally well done “Blood on the Southern Cross”.

I was expecting the latter to have a real bias, but found it was approached really well, and came away from the 90 minute sound and light show (including multiple locations) really impressed with how it was depicted.

From a shed-dweller’s perspective, there is so much of interest at Sovereign Hill.  From the construction of the buildings and fences, through to the metal and woodworking (both manual, and steam-powered) that you get to observe first-hand, but more on that in future posts.

Really got me wondering if I had been born about 150 years too late – the combination of wood, metal and steam, and how they were worked really resonates with me.

If you take a modern wood or metal worker, they would be pretty at home in the workshops from that era, and take an artisan from that period and drop them in one of our workshops, and they would hardly notice a difference, other than the absence of line drives, belts and steam – all replaced with electric motors.  The machines themselves – not much has changed, other than perhaps the addition of shielding!!

I haven’t even touched on the topics I will get into in upcoming posts, that deserve their own dedicated attention. Not to mention that the two full days we spent there (Wed afternoon to Fri morning) still didn’t leave enough time to do everything that was available to do or see!

Bottom line, if you have an opportunity to go to Sovereign Hill (and haven’t already), it is a real experience.

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Horsepower 

Having just spent 3 days in Ballarat, what have I just bought back to add to my shed’s ambience, that typically involves horsepower, but needs plenty of steam power to produce, that regularly comes in sizes 3′, 3.5′ & 4’?

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