Strine

In relation to the being sure you supply straight string with your Chrissy prezzy; liken it to sending the apprentice chainman down the street for said plumb bob and asking him, while he's there, to purchase a can of striped paint. Such paint is often required for painting the plastic tape used to surround important survey marks in the hope they will be protected from blind dozer drivers. It must be emphasised to the lad that he should not get the chequered paint as that is used by the police for their crime scene tape.

In relation to the turn this thread has taken viz; that plumblines are not parallel and that we have suddenly become very concerned about the effect this might have in a civil engineering sense a couple of points should be noted.

The novice surveyor might well assume that a plumb bob points to the "centre of the earth". Posts up until this point seem to suggest that this centre is a defined point somewhere down in the hot, sloppy part of the earth, and no matter from what part of the earth you hang your bob, it points to it. A plumb bob will point to the centre of mass or centre of gravity of all the stuff below it. In other words it aligns itself with the direction of gravity for the particular location. For those that wish to be further enlightened as to where a plumb bob might point it would be pertinent to find out the difference between the "Geoid" and the "Spheroid". Basically the former is the actual shape of the earth as defined by how the oceans lay - lumpy and bumpy on a grand scale as well as on a small scale where the lumpies and bumpies are just waves or swell. The latter is a mathematically derived "best fit" of the Geoid. This allows for the simplification of computations in developing maps and the like.

Having made these rash statements and you all believe I'm telling porkies, consider this. We can generally say a bob hangs vertical lest the wind is blowing on it. Gravity is doing its thing for sure, just as it does in making the surface of a body of water flat. I use the term "flat" hesitantly and only to make the illustration, for we all know that if it was flat we would have lost a lot of sailors over the years. I should have said level, because "level" is defined as being at right angles to vertical. So what happens twice every day at the nearest beach to your location. Correct... the tide comes in. It doesn't come in because the earth tilts and all the water sloshes over to your side. It comes in because the centre of gravity changes. Water never lies "off level" it always lies level, i.e. at right angles to vertical. If it did lie off level my kids could have had a swimming pool in the backyard which is sloped. But hang on, vertical is defined by our Chrissy prezzy plumb bob. What a dilemma, not only does a plumb bob point to different centres of the earth depending on where you are, it changes through out the day.

Just to make things worse. Have you ever noticed that having spent a good few minutes stopping your plumb bob from swinging it starts swinging again as soon as you turn your back. Believe the apprentice when he vehemently denies touching it as it is just another earth science thingo to worry about. It's not that fickle gravity this time but earth rotation. The bob is continually trying to catch up to where it's supposed to be given that it should be hanging vertical but someone keeps moving the goal posts.

Finally, congrats on the comps HW you're spot on except the concept is misplaced. The Sears Tower (we need to talk about this size structure since the average chook house is far too small to warrant such in depth discussion) is 1451.1 ft tall and let's say 360 ft wide at the bottom. Had the tower been merely a rectangular block (some architects are that boring) and the corners aligned with Elkdocs plumb bob on the end of a really long piece of string, the top floor would be about 2" wider than the bottom floor.

The moral is that the Earth is one big lump of stuff and what we do in our own little sphere of interest whether its a sky scraper or an outside dunny is infintesimally small in comparison. The design of the plumb bob is therefor open to your own interpretation, go wild.

Mmmm that was fun :D

Ahhhhh the plumb bob; most useful tool in a surveyor's kit. Having been one (a surveyor, not a plumb bob) for 35 years I can shine some light on the subject. Essentially everyone is right so far. It's a weight attached to a string which hangs vertical. A good one should be about 16 oz in weight, carrot shaped (pointy end down) with a hardened steel tip. It should be weighted evenly about the central axis which should be the line from where the string leaves the bob to the point at the bottom. Survey suppliers that I've had anything to do with usually only stock the brass models. Oh, and there should be somewhere on the bob to wind the string onto. There could be nothing worse than a length of string floating around in a tool box or carpenter's nail bag

But it is more than a weight on a string, and if we're not talking accuracy a brick would suffice. It's a make do hammer, a digging tool for looking for elusive survey points, a chisel for making "chisel cut in concrete", a toy to swing around and play with during slack moments, a source of string in an emergency, a sighter to look at through the theodolite, a device useful in setting the theodolite exactly where you want it, a drawing instrument for making mud maps in the dirt, a dog deterent, a paper weight for holding down plans layed out on the bonnet (hood) of the survey vehicle and there are many more applications that slip the mind momentarily.

Elkdoc I Hope this gives an insight into what a plumb bob could be used for. Whatever you make, of absolute importance, whether it be for accurate survey work accurate carpentry or just a bit of bush carpentry, make sure you supply a straight bit of string and what ever you do avoid string that hangs off vertical.

Gee I thought we had it bad with the odd tiger or brown snake to worry about or even the occasional drop bear that you think is lurking nearby, but I'd rather have them than all those pesky little things.

Karl, you're young, probably fit and healthy, probably don't have evil tendencies and seem keen to work.

Just do it. Get on a plane and go, or as we would say "up stumps and leave"

Go to the Australian Embassy in Stockholm and discuss your wishes with them. They will advise on immigration etc.

Once you're in the country THEN start the search for work. There's plenty around if you're willing.

When you get here "give us a oi and I'll shout you a beer"

I see red when someone comes along and pokes his bit of stuff into the fire. Just when I've managed to balance a piece of coke here and another one there for a specific purpose such as to protect a fine point. This usually happens at 'away games' where there's lots of smiths and less forges. No matter, I just walk away, taking the chance for a spell. Common courtesy wouldn't hurt though.

Hey Lads and lasses, with apologies to Dorothea Mackellar, it's a sunburnt country, sweeping plains, ragged mountain ranges, droughts, flooding rains, far horizons, jewel seas, the beauty and the terror ...it's the wide brown land for Karl.

You have to be Australian to understand the impact Dorothea's "My Country" has on the populous.

http://www.imagesaustralia.com/mycountry.htm ... catchy tune eh?

Sentimentality and parochialism aside I thought Karl wants to work over here.

Imagine what those wreckers could have got for a bell as pictured by Irn, on Ebay :shock: had they displayed a bit of forward thinking, like....gee I wonder if someone will invent a system that will revolutionise communication around the world.

And it strikes me as ironic that 'modern' only lasts a few years whilst 'the old' (read quality, workmanship, timeless designs) rarely loose favour in the long run.

A demagnetiser is something I've been after for years. TenHammers, I've got plenty of shirt pockets but what exactly is the thing called and where would you get one.

True enough Thomo. But you shouldn't have any worries if your a fine upstanding citizen of your country, have a bachelor's (master's would be better) degree in something or other and a couple of trade certificates Otherwise hide yourself away in a leaky boat fit only to sail on a small lake, and even then only close to the shoreline and we will treat you like the queen no questions asked. The Government will provide your board and lodging for a couple of years in the desert which is what you are after and then you are home and hosed :x

Don't know what happened to the art iron job link cos it doesn't work for me now. Ah well :cry:


Ah! that's a neat trick. Try this

http://tinyurl.com/dxqxu

I did a quick Google search for "jackaroo jobs". Here are two sites that talk about employment on station properties. If that's what you want. I say again a jackaroo does not dedicate all of his time to blacksmithing, in essence he is an apprentice Station Manager.

http://www.jumbuckpastoral.com/
http://www.pastoral.com/recruitment.html

Then I searched for "apprentice blacksmith australia" and found this

http://tinyurl.com/a5acxurl

You will need to put all this on one line with no gaps

It's an "Iron Art Traineeship" in Wagga Wagga (pronounced Wogga Wogga) which is in central New South Wales. Er don't ever call Wagga Wagga Wagga :wink:


Edit:url adjusted

Found it ... thanks lads

I give up :cry: Can anyone please direct me to the thread that discussed making a blower from a clothes dryer. I now have a stripped down clothes dryer and wouldn't mind giving it a go.

The same can be done with round tubing as well, if you don't like the line of the square tubing. It's a surprisingly strong joint. I bet it's perfect too for joining the cross members of a kite frame but in PVC not steel. Weeee......

Strine here Karl...Australian down to my bootlaces. Is the word you are looking for "Jackaroo". A jackaroo is a young bloke who works in the "Outback" on cattle stations or sheep runs. These are large farms or as the Americans say ranches. Some are a millions of acres in area where they run cattle at less than one to the acre. Lots of horses, lots of desert and they provide bed and lodging. There is usually some sort of blacksmith shop on each property since in the outback it is often a matter of self suffiency. You want it, you probably have to make it.

A jackaroo hopes to learn how to run a station and works at all sorts of jobs not just blacksmithing.

LOL, Yes Irn I did say, just as you said about your offering but I was too dopey to notice.

Thommo,
Here's a hope chest/glory box/quilt chest/sea chest I made for my daughter's sixteenth birthday. Made of Huon Pine; it was sixteen years in the making. Huon is a rare, beautifully grained and sweetly perfumed wood, found only in Tasmania...the big island south of mainland Australia and is obtained from the bottom of creeks and rivers and lakes where the logs may have lain for a thousand years. The species grows for thousands of years anyway.

Made by you Irnsgn? You don't actually say.

I got mixed up, I thought I was looking at the "Build a Story" thread. Good yarn Irn.

I can just hear them, 50 years from now, around the Chrissy dinner table... "D' ya 'member when Grampa fell down the well?"

Aha Doc. So it's not such a big mallet. I would dispense with the rings all together and use a bit of yellow box or iron bark; density about 1.12 tonnes/m3 ie it's wood what don't float. Yellow box or iron bark (eucalypt species) is readily available here but I don't know about where you are. Any heavy tough wood would do. Save your pattern for when it wears out so's you can replace it.

Yes Ed it really does work. My thoughts on the matter are that it is the tightness of the fit that will keep the rings on. The tighter the better. I'm probably barking up the wrong tree as to what this mallet is for but if it's for maul work it will want to impart some mighty blows. There is not much light work for a maul. So the will of the ring to maintain the laws of momentum conservation and continue on as the head hits its target and stops dead is immense.

I'm sticking with the flaired rings as well as the few old mauls I've come across all had flaired rings.

And I agree about the one piece mallet. The bush carpenters I know just grab a chunk of split fire wood, say a 4 or 5 inch billet 12 to 15 inches long and carve out a handle with the axe. The working end is left in the original shape what ever that might be...triangular, square what ever. They never roll away that's for sure.

Since the mallet/maul is to be made on the lathe. I would make the rings first. Then turn the head making allowance for thermal expansion. No body has mentioned it yet as it seems fairly obvious...the cold iron ring ID is smaller in circumference than the cold lump of wood OD by the allowance for thermal expansion. The rings should also be slightly flaired. So that the more work the maul does the more the face is driven into the flair preventing the ring from taking flight.

When turning the head, cut a groove about 3/8 to 1/2 inch from the outside diameter as deep as possible. LOL, too deep and and you'll send the turning chisel for a trip round the workshop. Funny before it happens, not so after! Be careful

Heat the rings and whack them on the maul as already suggested. Then drive wedges into that groove you cut at the lathe. Jobs done.

Oh, also, 'tis a wonderful thing to see an "s" on the end of our friend, nay... our soul mate, Mathematics

No Irnsrgn your anscetors, gee there's a lot of them, were not wrong. I hope I didn't leave that impression if so it was unintended. It's like this. You're three hundred miles from home, you've just spent the weekend bashing away at hot metal, generally for nothing and finally knock off time has arrived. You know there's a ton of stuff to load on to the ute, you relish the thought of a three hour drive home, four if you don't move now, You're cringing at how you will fair for a 5am start in the morning and of course it is impossible to finish such a weekend without enjoying a couple of beers with your blacksmithing mates. Is that incentive enough to douse the forge and fire pot in water, cool it down quick and hit the road. Sure is but I don't, plain and simple. And having spent all that hand cranking to keep the fire going while working I'm not about to douse, sprinkle or spray any sort of moisture on to it to reduce the fire. That makes me different, not wrong just different, but rest assured I wont loose any sleep over it. It's small beans compared to the heaftier woes of the world.

I assume by twyer you mean the fire pot not the air supply inlet. I have used an unlined cast iron fire pot for years with out any drama. It's an upside down pyramiddy shape about 1/2" thick all over. Actually, come to think of it, it's two halves bolted together and that might be why any cracking stresses are relieved. It's the same now as it was when I got it cast, except for the rust..er.. patina. It's forerunner was an upsidedown cone thing in one complete unit. Eventually it cracked but didn't fall apart and was, and still is quite usable. I never apply water to the fire nor cool the pot down with water at the end of the day. I reckon that's just asking for trouble.



This shows the bottom where the air goes in

Gobbler and Nolano.

Don't know whether you've noticed but along with the Emu, the Kangaroo is part of our national coat of arms.



He's the one on the left. Why? because neither species is physiologically able to take a backward step. ie to walk backwards. Cool eh? Oh and the foliage is "Golden Wattle"

They're hard to get because any culling etc is strickly controlled. They are indeed a protected species. I met a shooter in the bush one time and asked/pleaded for a skin. "Oh no I can't" he said "I'd lose my licence if I don't have the right paperwork etc etc.

On the other hand I met a bloke in a pub and we arranged to go out the next night to his mate's farm. Farmers can knock a few on the head from time to time and it's all above board.

But go to a leather shop and all you can get is the skin john west rejected.

1 ten thou accuracy is the same accuracy as marking out a kilometre to the nearest 100mm...easiest thing in the world to achieve with the right tools but it costs money...big money. You can't do it with a ten dollar plastic tape measure. Tell the bloke that to achieve such accuracy is going mean his you-beaut interferometer will be so expensive it won't have a market and he's wasting your time and his.

Allow me to tell a yarn about an engineer I did a job for. We were building a roof over a reservoir, maybe five acres in area. The roof was to be held up with vertical "I" beams at around five metre centres. The I beams were to be supported on concrete pads, caste in situ with four holding down bolts. My job was to set out the location of each holding down bolt. The engineer required half millimetre accuracy. After much negotiating and telling him he was insane we managed to get it out to 1mm. Had it got to 5mm the cost of setout would have reduced by 80%. The accusations of insanity remained but they were kept in house.
Do you know a concreter that can work to 1mm? No, and the engineer didn't either because as it turned out, after all the expensive survey work the most useful tool on site when the I beams arrived was a 14 pound sledge hammer :wink:

So as the half millimetre was just a fanciful number to the engineer so too might the ten thou be to your mate. Baffle him with science. Ask him to explain to the nth degree why it has to be so accurate. Whether you understand it or not, pounce on any hestitation with suggestions of less accuracy. You might strike it lucky and get to the 0.002" MM suggests

Another solution to the problem is to point out that he is jeopardising his relationship with you as a mate with such difficult conundrums and that he should only consult you for answers to the easy things like what is the meaning of life or what existed before the big bang if there was a big bang.

Can you build/fabricate the hole around an accurately machined core then take out the core.

I think I'll move on to the next problem solving thread

Good luck T