I prefer casting as it means:- a: Less work b: Less expense (electricity is prohibitive in price here) and buying billets of Al versus getting it for free means it's a no brainer...Yet all the time I see items which are (imho) better suited to casting than machining being produced...From the swarf cut out of these items I could run a new part off :D So whats the lowdown on this billet buying frenzy folks :)

not everyone has a way to cast the aluminum. i plan on machining alot of my brackets out of aluminum because i don't want the hassle of casting this at home. now if i go out to shop to have the casting done, it will be expesive...read more expensive than me machining it.

Billets usually have the benefit of having some rolling or forming operations performed on them. The intentionaly yielding of the material tends to work harden it thus adding ductility to the metal. This makes it "tougher" (more area under the stress-strain curve).

Castings are quite suitable for near net shape items - especially, complex shapes that defy traditional machining methods.

Billets tend to resist tensile loadings better than castings and are inherently more robust than castings.

Examples for illustrative purposes: A cast cylinder head is both durable and affordable. Billet heads are made and are FAR stronger than mere castings BUT, they are horribly expensive. They also do NOT have good properties for long term operation due to the fact that they don't have the internal water passages that cast heads do.

On the other hand, forged con rods are constantly subjected to violent swings in compressive followed by tensile loadings. Although Briggs and Stratton made die cast rods for lawn mower engines, aluminum con rods (mostly used in drag racing) are made of either forged billets or bar stock billets - they are simply stronger.

NOTE: both billets and castings start off as molten metal that are poured into a form to make a basic shape/slab of metal to begin with. Stuff that will be wrought into a billet recieves subsequent hot and/or cold forming to work the metal so as to revise the grain stucture so as to better taylor/obtain the desired properties of the metal.

Metal that will be cast is simply molten and the desired alloy mix achieved and then poured into molds. In some cases, the metal is poured into molds so that the metal can be stored as a "virgin" alloy for remelt later.

There's more to consider but this should get you a basic understanding.

.... So whats the lowdown on this billet buying frenzy folks :)

There is a certain mystique to saying something is made out of 'billet aluminum'; it almost has the same ring as 'made out of aircraft alloys'. There are practical reasons for using extruded or forged (i.e. billet) aluminum because then you have defined properties, often the surface finish can be far better and anodizing is easier.

Key words in Geof's post "defined properties".

When you check out the propreties of the material, be it billet/wrought material or simple castings, you'll see that there can be HUGE differences between the materials and the properties associated with them in their particular form.

Yes, there is "magic" in the definition but it is also definite differences in material properties.

I'll be sure to obtain a basic understanding of the whole process someday ;) meanwhile i'll keep on casting :yay: My point was why is the whole world seemingly machining 90% of the Al away to end up with a simple shape! The voting is a good indication as to why...people maybe think casting is beyond them (it's not in any way) or they dont yet have the method to do it...or the drive to try it. As far as "magic" try opening the flask to find a perfect casting in there...theres no better feeling than to make it with your hands :yes:

So whats the lowdown on this billet buying frenzy folks :)

the low down is a pile of crap imo - this is nice crowd here but on some of the sites you'd better duck for cover if you call AL bar stock 'billet' :D

My pet peeve is that rolled bar stock or plate of AL is NOT billet. Billet isn't a grage or alloy, its a bulk shape and size when AL that comes from the smelter enroute to the extruder. its a pet peeve because the word is so erroneously used, many uninformed thinks something made from billet is special vs if told them it was made from AL bar stock or the particular alloy. "I made this out of 7075" "ah man, you shoulda gone quality used billet". ARRRRG. make it out of 6061 call it billet and charge twice as much, doesn't seem right to me.

iirc billet specifically refers to the round shape that is loaded into extrusion machines, ingot being the more generic term for a bulk shape that may go on to be cast or rolled. in any event, both are cast - a billet is cast AL of in more advanced plants continuous cast AL , you can't get it alloyed so its ready for an extruding machine if the metal isn't molten. if you are going to call it billet, it least apply the stupid tax and double the price vs if it was made of AL :D

to the original point, I've done AL casting but would really like to try the lost foam AL casting, neat stuff. next up would be iron/steel casting or better yet lost foam iron/steel casting. then again, one must know when to stop!

the low down is a pile of crap imo - this is nice crowd here but on some of the sites you'd better duck for cover if you call AL bar stock 'billet' :D....

You must have been working late 7 posts down. Notice how I discreetly skated around the subject.

Kipper; to find out a bit about what my compatriot is ranting about do a search using the word 'hermeneutics' and read through the thread you will get.

You must have been working late 7 posts down. Notice how I discreetly skated around the subject.
.

Geof you crack me up, needed that. see, that is why you could get elected while I'm still whinin' about the government! hehe but hey I did put the smiley in - even though i'm crusty at the end of the week I try not to take myself toooo seriously, after all no one else does. (chair)

My point was why is the whole world seemingly machining 90% of the Al away to end up with a simple shape! The voting is a good indication as to why...people maybe think casting is beyond them (it's not in any way) or they dont yet have the method to do it...or the drive to try it. As far as "magic" try opening the flask to find a perfect casting in there...theres no better feeling than to make it with your hands :yes:

Kipper,

You summed it up. Never underestimate the combined power of ignorance and laziness. It exercises more force than the biggest lathes or mills imaginable.

I can't imagine a better time to be entering the small foundry area, either individually or for small enterprises as part of manufacturing operations. The combination of low cost CNC pattern making and lost styrofoam casting reduces start up and operations costs by unbelievable amounts.

Mark

Hi Kipp, back in '75 I did some alluminium casting using the varied and dubious quality of old washing machine bodies, piles of extruded ally swarf from turnings, and any other metal that looked silvery, light and scratched easily with a nail. I kid thee not!
To melt the mix we made an enclosure with a few firebricks laid out in a square, and used a large steel ladle, formally used for melting lead.
This was heated with a Sievert propane torch and gave us about a litre of melt material.
The casting was done by placing steel blocks together to form a cavity 75mm X 75mm and approx 100mm deep.
The metal was simply poured into this up to the brim and on cooling the steel blocks just fell away and we had "billets" of ally.
We cast many billets this way. The only thing you have to observe is that if a specific length is required then you just increase it by a half to allow for the shrinkage and the impurities which will be at the top.
The machining qualities were very good despite the varied mix.
We never used any cast alluminium, as was available in car gearboxes, due to the rough and porous nature of the metal.
I'm not an expert in alluminium but I think the alluminium castings as used in gearboxes and the like is silicon alluminium.
This material machines well, but only if you're into production, and want to prevent the long stringy swarf that extruded and sheet alluminium produces.
When you turn the stuff, the swarf breaks up the same as you get when cutting freecutting or leaded steel, but it is also prone to blow holes and rough inclusions, really crap stuff.
The texture of the cast gearbox ally is rough and brittle, with little black bits in the metal, and does not have any ductile qualities at all.
If you strike the casting with a hammer it will yield and break up into bits.
We also added a bit of Mazac or zink castings to our mix, in the form of carburettor bodies and this had the effect of making the alluminium harder to machine and produced a bright shiny allmost glazed appearance when machined.
My last excursion into melting was with a wood fired kiln type of furnace and gave two litres of mix per firing, but the furnace was hard to use and required constant charging and cleaning.
For a few simple castings, such as square or round stock for turning etc then steel moulds will give good results, making sure that allowance is made for the shrinkage and impurities rising to the top.
One of the "molds" we made was from steel, for an alluminium hammer for use on the milling machine when tapping down the job in the vice.
The mold was split, held together with hose clips and stood upright.
Then the metal was poured down the handle and on cooling had shrunk 50mm.
No special preperation was applied to the steel and no problems were encountered in the final casting.
Simple and cost little.
My next "have a go" will be electric, for alluminium, using 2KW elements wound in a spiral inside a fire brick enclosure to give about 1 litre of metal for a few projects I've got in mind. I'll probably use a steel crucible coated inside with a Plumbago wash.
Ian.

Ian,

>>but it is also prone to blow holes and rough inclusions, really crap stuff.<<

Mostly that's a sign of hydrogen porosity, which almost always arises from moisture. Preheating the scrap, furnace and crucible to 400 - separately - will get rid of most of this. In aluminum founding with locally built small and likely inefficient foundries, the charge pre-heat will also get you a running start. Pre-heat can be as simple as a rebar grate and a scrap pallet wood fire.

>>the alluminium castings as used in gearboxes and the like is silicon alluminium.<<

Alloy 356 or similar is usually used for these sorts of castings. They run around 7% silicon.

Mark

Thanks for the comments guys :cheers: I melted around 50KG of castings today as I ran out of ingots thursday. I need a cover casting tomorrow and to reduce the bulk of the scrap pile so it'll be hot in the garage :) I started casting around 20 years ago in my backgarden in a dustbin using wood offcuts to melt it with fan assistance, then progressed to gas fired and ended up with gasoil (diesel) firing as I find it clean and cheap (for me) I played around with cast iron at one point and may have a need to use CI soon. I learned early on that StSt is no good as the Al just eats it! although I still use StSt to stir and break up the castings, i'd get a morganite graphite crucible but the impurities mentioned relating to melting in steel crucibles has never materialised for me (lucky eh D) Theres a good source of home cooking recipes for Al alloying at backyard metalcasting I believe ( I thought pistons had the highest amount of Si in them? I avoid them like the plague lol) Happy machining All

Hi Kip, as far as I know pistons are made from stuff called LO-EX which means low expansion. These were always put aside in scrap yards and sold as special alloy metals. That's all I know.
Back in 1975 when I was in Uk I met a bunch of gypsies or travellers, and they used to collect scrap metal as an occupation.
One of their methods was to get a whole load of car gearboxes and the like, and scoop a large shallow hole in the ground, about 3 metres round and 1/2 metre deep, then a pile of wood was built up with the gearboxes in the middle and the whole lot fired up.
When the fire had died down they took long rakes and scooped all the steel bits out of the "puddle of ally" and let it go cold.
This was then taken to the nearest scrap metal yard and sold as a solid lump of ally 3 metres round and 1/2 metre deep.
I've heard about steel not being the best thing to work with ally,but one pot I made from 1/8" steel sheet, about a litre capacity,was still going strong a year later at a mates place.
What is the actual effect of using steel with ally?
Ian.

I believe it's supposed to absorb the iron and "does terrible things to the alloy" I like old oxygen bottles as they are very thick ergo safe...ish :D Dinner time here in the UK :wave:

What is the actual effect of using steel with ally?
Ian.

Molten aluminum dissolves steel; actually to get picky it dissolves the iron in the steel. The iron content makes the alloy brittle. Silicon improves the fluidity of molten aluminum and allows it to flow into fine detail better.

When it comes to "mission" or application critical strength or other required properties, by all means, BUY what you want/need - the chances of a non-metallurgically trained person to melt and pour exactly what they need are quite remote.

I know of some scrap dealers who won't accept "mixed" scrap that they can't readily identify the alloy of. Why? Because if you dump the wrong or contaminated scrap into a vat of molten aluminum (contaminated with copper, zinc, iron/steel, whatever) you end up with junk.

Comparing the metallurgical requirements of a transmission case to that of a piston, wing spar or whatever is hardly a suitable decision to be made by a hobby level metal worker.

Similarly, trying to home melt metal that will meet any/all of these requirements (from swarf, beer cans, whatever) is also a bit beyond the pale of the average DIY'er.

Regarding transmission cases or other devices that simply need cross sectional mass, one could probably cast up a reasonable home brew of alloy and it would work fairly well. Machining might be an issue as might porosity but it would probably work.

Now, lets say you want to machine up a connecting rod or some other device that needs to do more than just "hold up". When you are going to subject a part to repeated load reversals or high tensile loads, you need a material with RELIABLE metallurgical properties AND properties that are TAYLORED for that particular application.

There's nothing wrong with experimentation with aluminum foundry practices and casting. However, to simply cook up a batch of metal to pour into a mold in one's back yard may result in a material that simply doesn't have the properties suitable for the intended application.

Alloy content is but a small portion of what goes into creating a suitable material. Subsequent cold and hot forming along with heat treating are critical to the creation and tailoring of materials suitable to a task. Some of these are not readily duplicable by the DIY'er.

If you know what you're doing and can create the alloy structure that is appropriate for the task, go ahead and cast it. Otherwise, you might be better served by buying a piece of metal that is already alloyed and heat treated so that the bar has the properties that you need.

Some people call this semi-prefinished/formed piece of metal stock as "billet". Others call it bar, some call it plate - some might even call it "ally".

When it comes to "mission" or application critical strength or other required properties, by all means, BUY what you want/need - the chances of a non-metallurgically trained person to melt and pour exactly what they need are quite remote.

I know of some scrap dealers who won't accept "mixed" scrap that they can't readily identify the alloy of. Why? Because if you dump the wrong or contaminated scrap into a vat of molten aluminum (contaminated with copper, zinc, iron/steel, whatever) you end up with junk.

Comparing the metallurgical requirements of a transmission case to that of a piston, wing spar or whatever is hardly a suitable decision to be made by a hobby level metal worker.

Similarly, trying to home melt metal that will meet any/all of these requirements (from swarf, beer cans, whatever) is also a bit beyond the pale of the average DIY'er.

Regarding transmission cases or other devices that simply need cross sectional mass, one could probably cast up a reasonable home brew of alloy and it would work fairly well. Machining might be an issue as might porosity but it would probably work.

Now, lets say you want to machine up a connecting rod or some other device that needs to do more than just "hold up". When you are going to subject a part to repeated load reversals or high tensile loads, you need a material with RELIABLE metallurgical properties AND properties that are TAYLORED for that particular application.

There's nothing wrong with experimentation with aluminum foundry practices and casting. However, to simply cook up a batch of metal to pour into a mold in one's back yard may result in a material that simply doesn't have the properties suitable for the intended application.

Alloy content is but a small portion of what goes into creating a suitable material. Subsequent cold and hot forming along with heat treating are critical to the creation and tailoring of materials suitable to a task. Some of these are not readily duplicable by the DIY'er.

If you know what you're doing and can create the alloy structure that is appropriate for the task, go ahead and cast it. Otherwise, you might be better served by buying a piece of metal that is already alloyed and heat treated so that the bar has the properties that you need.

Some people call this semi-prefinished/formed piece of metal stock as "billet". Others call it bar, some call it plate - some might even call it "ally".

"hey whats that smell?" I'll not be making anything going to the moon just yet.....However for replacing the bought in stuff ie billet alloy etc for making uprights on a mini router I kinda reckon it will hold up just fine...and then some ;) it may well be able to support a nema 23 motor and resist it's torsional forces :D rocket science it aint bud :cheers:

Hmm, alluminium iron, wonder what the properties are?
Ian.

Hmm, alluminium iron, wonder what the properties are?
Ian.

From: http://www.key-to-metals.com/Article55.htm

Iron is the most common impurity found in aluminum. It has a high solubility in molten aluminum and is therefore easily dissolved at all molten stages of production. The solubility of iron in the solid state is very low (~0.04%) and therefore, most of the iron present in aluminum over this amount appears as an intermetallic second phase in combination with aluminum and often other elements.

Hi, what effect does the iron have with the ally? does it enhance the "alloy" or cause other problems? I know alluminium bronze is a real lulu to work unless your tools are really sharp.
Ian.

"hey whats that smell?" I'll not be making anything going to the moon just yet.....However for replacing the bought in stuff ie billet alloy etc for making uprights on a mini router I kinda reckon it will hold up just fine...and then some ;) it may well be able to support a nema 23 motor and resist it's torsional forces :D rocket science it aint bud :cheers:

For playing around at a DIY level when you are the person who is going to suffer the consequences that is okay. But it is a different thing when the word 'manufacturing' is mentioned because that implies selling to a third party. Backyard cast aluminum of undefined composition from scrap is rarely adequate and can be downright dangerous. The 'billet mystique' I mentioned does have validity and it has grown out of the market for adapters and accessories in the modified motorcycle and offroad 4x4 market. Amateur cast aluminum does not cut it when you are making transmission adapters or fancy footpegs; giving the impression that maybe it can is not entirely responsible.

For playing around at a DIY level when you are the person who is going to suffer the consequences that is okay. But it is a different thing when the word 'manufacturing' is mentioned because that implies selling to a third party. Backyard cast aluminum of undefined composition from scrap is rarely adequate and can be downright dangerous. The 'billet mystique' I mentioned does have validity and it has grown out of the market for adapters and accessories in the modified motorcycle and offroad 4x4 market. Amateur cast aluminum does not cut it when you are making transmission adapters or fancy footpegs; giving the impression that maybe it can is not entirely responsible. SOoo dont mention footpegs or tranny adaptors and we're good to go :D Seriously nobody can hobbycast large amounts to enable manufacturing..In which case the ingots would be bought in and then it is a controlled alloy if melted down in a controlled way degassed etc of course depending on.....wait for it.....it's "intended" use ie in this case simple brackets covers and even carriers for bearings (had to type that small to keep from NC clobbering me over it lol) Nothing too stressful and no need to go into manned spaceflight metallurgy or risk assesments etc....As a pro caster said to me "Ally is nasty sticky stuff and you dont want it on you" the actual melting and pouring is the dangerous part. Ask yourself as a hobbyist how much does a 70mm square of "billet" cost? and how much to machine it into a motor mount..And then ask yourself how much to cast it and then just shave a little off to finish it. I can make a dozen for £5 but it would cost that to buy the material to make one :shrug: Alternatively I could use threaded rod and spacers and whatever is laying around and achieve exactly the same end but you wouldnt mention trick off road parts then would you :D lets not get carried away by imagining all the potential failings and use the methods that are available for the task at hand.

Hi, when it comes to manufacturing, i.E. to make something with the express intention of selling it to anyone who will buy it for your profit, then you shoulder all the responsibilities of potential litigation should your methods be not up to scratch.
Backyard workshops are spawning grounds for some of the most dangerous procedures adopted by man under the mistaken identity of "being in business".
It doesn't stop there, the methods to produce may be slipshod but the product may be first rate. On the other hand if you don't know what your working with, that is materials, design and assembly methods, then you will not only be "making a bomb" money wise, but also putting some poor barstewart at risk by your slap happy approach.
It all comes down to REPUTATION. When you've been in the game long enough and can show that you know what your doing, then you gain a modicum of respectability from your fellow humans,and your insurance premiums are not sky high to cover your ineptitude.
I don't think anyone with a bit of sense would willingly plunge into the deep end where the sharks prowl, which is what the business world is. So when you do a job with dubious materials and try to fob it off as "good quality" remember to apply for accreditation to get ISO 9000 or whatever the standard is and see what your up against.
I've done quite a few jobs for pecuniary advantage, using the most basic materials and methods, and there are those jobs that you just wouldn't touch with a barge pole. Why? Because to do those jobs requires the level of expertise that some of us profess to have but can't produce.
Expertise could be defined as to knowing what you're doing and have the necessary means to do it properly.
The other thing is it takes a lot of input in material and machinery to put the expertise to work, otherwise you cut corners to make it pay and end up making someone else pay.
When you cross the border from hobbyland to customerworld then you graduate from amateur to professional and shoulder all the responsibilities required.
By the way, I always understood ingots to be cast blocks from raw material, for conveniant handling and storage, and billets were always referred to as bar material that was cut to a specific length to enable a machine to handle it.
Such as where a lathe couldn't pass the material up the "pipe". Also forgings were referred to as ingots that had been reworked to a specific shape to reduce waste material and exceass machining.
Ian.

Ian,

>>The other thing is it takes a lot of input in material and machinery to put the expertise to work, otherwise you cut corners to make it pay and end up making someone else pay.<<

You've just described the world of free trade, GATT and WalMart. These are noble sentiments in theory, so long as they're not used as excuses for closing down competition with bogus regulations or price gouging customers. In reality all that happens is some drone with cash in his jeans takes a trip to China and India and arranges to import product made under the same conditions or worse conditions as you condemn domestically.

Mark

Hi charcad, I agree with you up to a point. If the goods come up to expectations then who am I to deny some peasant in a third world country a decent living by their standards.
The point I was making is when someone fobs off an item made in a backyard set-up that is purposely made from inferior materials and expects to be paid at top dollar then I get a bit snarly, as in GGGGGGRRRRR
This used to be the case with "Taiwanes terrors", or those mill/drills that came onto the market in the late '70s and were full of casting sand, made with crap machining methods, having missallignment so bad that you could detect it with a piece of taut string.
But they were cheap, and many people that bought them set to and reworked them to usable standards.
Take the Chinese lathes on the market today, especially the lower priced ones. I bet a weeks wages that NO-ONE without exception can make one to their quality for the same price.
If you didn't know it, and thought it was made in Germany or USA, how much would you expect to pay?
Then we get the fools who buy these machines and subject them to rough workshop handling by unskilled operators and scream out about the cheap rubbish they've just bought.
Dollar for dollar you will never match a peasant's wage to a western wage earner's wage.
Why do you think so many manufacturers go to third world countries to get their products made? Money, that's why and you and I are buying the stuff all the time, (and loving it).
When the government puts a tariff on all foreign imports to enable the home market to justify their wage earnings and so compete, you will also have to sell your goods at give away prices to match theirs.
Ian.

This used to be the case with "Taiwanes terrors", or those mill/drills that came onto the market in the late '70s and were full of casting sand, made with crap machining methods, having missallignment so bad that you could detect it with a piece of taut string.
But they were cheap, and many people that bought them set to and reworked them to usable standards.

They merely moved the patterns and production to mainland China. The 9x20s and 12x36s I've looked at in Harbor Freight are still full of casting sand and crap machining. Their basic methods - today - are identical to how Atlas Press and South Bend made lathes in the 1930s. They're just not as good at it. Do you suppose the Chinese are ageing their iron castings three months the way Atlas once did? FYI, the practice of ageing iron castings was recently shown (again) to have a basis in fact.

Take a look at these 2003 photos.

http://www.mini-lathe.com/Mini_lathe/Sieg/Sieg.htm

The 1937 Atlas Lathe manual has a series of nearly identical pictures.

Take the Chinese lathes on the market today, especially the lower priced ones. I bet a weeks wages that NO-ONE without exception can make one to their quality for the same price.

You mean the copies of the 1960s South Bend 'Heavy' design that ultimately proved most successful?

I recently acquired a pair of Atlas 10s. The 10x36 needs extensive restoration. But the spindle is still tight and if there is any ways wear its only detectable by dial indicator. The 10x24 was used by an old machinist who made carnival midway electro-mechanical widgets until last year, when he had a stroke. He's in his 80s. Plug 'n play condition because that old boy knew how to take care of his equipment. The prices were right. The first was 'free' for hauling it off. The second was $25, including a very full set of tooling.

Having one mint condition 1950s machine to compare, I can say the Chinese still haven't come up to Atlas' former standard of workmanship. They just have the benefit of copying the more recent 1960s South Bend heavy designs that were derived by applying finite element analysis to lathe design.

Here's another interesting comparison between a Rockwell drill press of the 1930s and what's sold at Harbor Freight today:

http://www.owwm.com/delta/1941DrillPress.asp
http://www.harborfreight.com/manuals/39000-39999/39955.PDF

I wish I could have found an old Rockwell like that in my area. I'd have bought it instantly rather than the 'new' Chinese drill press I got several years ago.

>>Then we get the fools who buy these machines and subject them to rough workshop handling by unskilled operators and scream out about the cheap rubbish they've just bought.<<

The difference is the machinist, not the gear. A true machinist will soon have great equipment even though he starts with junk. The fool can start with the latest Haas 5 axis VMC but will soon have only junk. In my opinion trained and motivated men are the only true 'capital'.

'Bigger and better' equipment affects production rate, not quality

>>Why do you think so many manufacturers go to third world countries to get their products made? Money, that's why and you and I are buying the stuff all the time, (and loving it).<<

Maybe you are buying it. I've sworn off. :nono: The real question is whether it's the western worker or western executive who is overpaid and underskilled. There are a lot of hidden costs only now being discovered. You cannot import third world products without ultimately importing third world wages and living conditions.

I spent a lot time in the third world before retiring from the US Army in my late 30s. These are all highly stratified societies with ruling classes based on family inheritance and ownership, not achievement. And with no social 'safety nets'. It's not uncommon for people to be left to die in ditches while multitudes pass by. Western 'capitalists', meaning those with access to cheap paper money and political influence, clearly think this is a great system. It's why more millions every year are losing their jobs and health insurance.

There is a difference between 'backyard' and 'professional'. It lies entirely in the people doing the work. Paper money is not magic and cannot convert one piece of gound into 'professional'.

My point is, don't overcomplicate things. One can quickly spend $6,000 buying foundry gear from Mifco that won't achieve any better result than is obtainable with shop made gear that 'cost' 5% as much to build. And if the foundryman with the $6,000 of 'professional' gear is no good then your better off using the pro who rolled his own equipment.

.....By the way, I always understood ingots to be cast blocks from raw material, for conveniant handling and storage, and billets were always referred to as bar material that was cut to a specific length to enable a machine to handle it......

Seems like I triggered a lot of useful verbosity with my mild comments:D ,

For the lowdown on billets, ingots, forged, extruded, etc., and much other stuff go to that thread I referenced. The one with the word hermeneutics. I think it is the only one you will pull up in the search.

Char, I have to agree with what you say wholeheartedly, but macinery made nowadays is not made to last.
The Chinese have learned the lesson that the western cultures have not. That is, make it cheap, make lots of it and make it wanted.
I've yet to see a buyer take a machine apart on the showroom floor and inspect it for flaws imperfections and bad paintwork.
Yes, bad paintwork was the reason that one of the people I worked with faulted a Taiwanese lathe. Apparently the lathe in question had that greenish crackle finish applied directly to the casting and it had flaked off in a few places due to handling in transit.
Car makers no longer make cars to last a century, and I doubt whether many people buy one to keep for any length of time. The Japanese taught us that.
One thing for sure, go down to your machinery dealers showroom and note the machines on his shop floor.
I hope we are not mistaking high quality machines made to very tight specifications with the other stuff which will outlast the majority of people that work them anyway.
Have you ever seen the guy who when he goes to buy a used car lifts the bonnet (yep, it's got an engine) and then looks in the boot (yep got a spare tyre too) and then kicks the tyre (yep, got air in this one)?
A similar guy I saw at our local machinery dealer was rolling the saddle up and down a lathe bed and muttering to himself, then he gripped the chuck and turned it around and around a few times, finaly he wiped a finger across the chipped and rough paint on the headstock and said 'load of ole' crap'. Interpreted to mean I can't afford it so I'll just rubbish it.
What you say about importing third world wages is the ultimate cost of not recognising a trend or need.
When the industries close down against competition it is always on price, never on quality. Jap cars USA cars.
The customer is always right and will decide your fate. How patriotic can you get to buy a cheap foreign import when your own products are standing there.
By the way aren't Bridgeports now cast in Taiwan and made there or have I got it wrong?
Like I said the imports should have had a stiff tariff applied so that all "patriotic" buyers would have the choice to buy at the same price a foreign import or the real Mcoy home grown. What would you buy then? A genuine Bridgeport or a Taiwanese look alike?
Admitted you wouldn't be able to export to China because they would have gone broke seeing as no-one was buying their machines. This would also mean that your export goods wouldn't sell either.
The only way you'd be able to make cheap good quality machinery is if you went to a third world country, like anyone else, and got them to make it, and then import it and flog it on Ebay cheap. The old adage "never mind the quality, feel the width" is so true.
In the western society we have a higher standard of living, because we have ethics and tend to want to have regulations and standards. We are governed by the need to aspire and achieve.
The backyard business is by and large a mongrel with no credibility save being able to do it cheaper. Once you have become established and are able to prove that you have what it takes then you don't spoil it all by letting your standards slip.
The fact that it is a backyard business speaks for itself. Certainly not by choice does someone work 7 days a week and 12 hours a day.
In these circumstances all the niceties of safety regulations get overlooked and quality control becomes an urban myth.
Ian.

So when you do a job with dubious materials and try to fob it off as "good quality" remember to apply for accreditation to get ISO 9000 or whatever the standard is and see what your up against.Ian.

Ian,

I understood what you meant is 'meets or exceeds specification'.

But ISO 9001 has nothing to do with that. It's another advertising scam like 'free trade' and 'paper money'. The occurrence of ISO 9001 certification and 'quality' in the same place is coincidence, not cause and effect. I will say that ISO 9001 cert and higher product costs is cause and effect. It takes lots of time and often expensive consultants to meet the requirements.

Great article here on ISO 9001. http://en.wikipedia.org/wiki/ISO_9001

ISO 9000 does not guarantee the quality of end products and services; rather, it certifies that consistent business processes are being applied.

I love the pic of the ISO 9001 certified fish market. If we swim down to the school of fish will we find the ISO 9001 compliance fish someplace on the reef? :) I wonder where the compliance fish keeps his files?

I joined the Army at 17. Before I retired to civilian life and work I thought it was the only organization stupid enough to think generating mountains of paper forms could guarantee consistent outcomes. Instead I discovered this superstition has more believers than any other religion.

Mark

....ISO 9000 does not guarantee the quality of end products and services; rather, it certifies that consistent business processes are being applied....


You must have found how difficult it is to convince people this is what ISO 9000 really means. You can be producing utter crap and have ISO 9000 and what it means is you have the procedures in place to make sure you do not accidentally make something worthwhile.

Ian,

Unfortunately I've never been to Australia, so I can't speak to 'backyard' conditions there. I still want to go Down Under some day.

The fact that it is a backyard business speaks for itself. Certainly not by choice does someone work 7 days a week and 12 hours a day.
In these circumstances all the niceties of safety regulations get overlooked and quality control becomes an urban myth.

A friend of mine here in Florida ran a one man 'backyard' machine shop in Connecticut in the 1970s. Actually a home garage machine shop. Ted still says his dad was a machinist but he never was. That's mainly Ted's attitude towards quality and knowledge.

Anyway, among "not a machinist" Ted's contracts was one for making all the elevator, aileron and rudder hinge sets for the A-10 Warthog. He made over 1,000 hinge sets using a Bridgeport mill and Hardinge lathe in his garage. Contractor and USAF inspectors used to come to his shop to inspect 'production'.

You might be shocked at how much 'hi-tech' ends up being sub-sub-sub contracted out that way. No fancy two glass mirrored window industrial park location, just someone who knows what he's really doing.

Regards,

Mark

Hi Char, yep I know what you mean. But paying lip service to the standards of industry is just another example of the lack of self discipline that it takes to become a leader in the industrial rat race, and not necessary a top producer.
Abe Linc said "you can fool some of the people some of the time etc etc." So if the guidelines of industry are just ignored how can you be proud of your achievments.
It's a bit like everyone printing their own money and passing it around. Well I suppose you do write cheques and pass them around.
If you're that good at what you do and can impress enough people with your standard of workmanship then your fame will go before you and no-one will question your work.
When I worked in the UK some years back a firm I worked for did sub-contract jobs for Rolls Royce.
The parts we made were all checked by the person making them and then delivered to RR.
We were responsible for our own individual QC and as such took great care in the final product.
There was no room for error and 100% acceptance was achieved.
Many of the parts went on Concorde and various military aircraft.
We did not have ISO 9001 or anything like it then in 1975.
ISO 9001 on your business card is an indication of business integrity and indicates that you are professional enough to mean what it says.
I suppose there will always be those that have testimonials hanging on their walls for colleges they've never been to. Some desperately need it when all else fails.
Ian.

You must have found how difficult it is to convince people this is what ISO 9000 really means.

Sometimes. There is a widespread myth that ISO cert somehow makes faceless long distance transactions 'safer'. I think it plays a supporting role in the Legend of the Benefits of International Free Trade.

You can be producing utter crap and have ISO 9000 and what it means is you have the procedures in place to make sure you do not accidentally make something worthwhile.

Exactly.

Hi Char, re post #17, where I last worked our toolroom chargehand left after many years to go full time on his own business.
He is a very meticulous toolmaker by trade and couldn't abide sloppy workmanship. One of the reasons why he left was dealing with people that tried to fob off work that was second rate and worse.
There will always be those people who value pride of workmanship above all else.
Incidently when the firm aquired accreditation to ISO 9001 we would get surprise visits from the bureau of standards to make sure we were complying with the rules.
I don't know how anyone can get away with sloppy standards. On one occasion we slipped up and we were given a warning and a time limit to get back in line.
Ian.

Backyard business generally refers to those set-ups where an old worn out bit of machinery is persuaded to perform miracles above and beyond the expectations of the makers when the machine was new. Also material is gleaned from scrap metal yards with no pedigree whatsoever, as long as it's cheap.
Ian.

G'nite all I'm off to bed, it's 4 AM and I've turned into a pumpkin.
Ian.

... Legend of the Benefits of International Free Trade.....

Hey don't knock Free Trade, we export to 14 countries including the U.S. of A. :)

Backyard business generally refers to those set-ups where an old worn out bit of machinery is persuaded to perform miracles above and beyond the expectations of the makers when the machine was new.

Ian,

Isn't being on specification and time with contracted product the most important part? Or am I missing something? :confused:

Also material is gleaned from scrap metal yards with no pedigree whatsoever, as long as it's cheap.
Ian.

If someone is substituting below standard materials to what's specified or known to be required, then I agree with you. That's fraud. Reverting to the 'Ted A-10' example, he mentioned the government inspectors were hot about making certain he was only using the steel stock he'd been supplied, and that material substitution wasn't occurring.

'Gold plating' is equally wasteful and can needlessly cost the customer extra money.

'Caveat emptor' still applies no matter how much paperwork we try to wrap around it. If the 'specification' permits it, what's wrong with using 'junk'? GM, every mini-mill in the country and the Chinese all make extensive use of scrap metals.

In my opinion metal part problems arise more often from improper or omitted heat treating than from using improper alloys or even hydrogen porosity in aluminum.

Mark

Threadjacked :D

Re: improper heat treat vs improper alloys

Take 4150 and harden and draw it to an Rc58 (easy to do).

Take O6 tool steel and H/D it to same spec hardness. Again easy to do.

When you compare the scuff resistance of O6 to 4150 when subjected to high loads and marginal lubrication, HUGE difference and that occurs even though the parts are of the same hardness.

Hardness and tribology are NOT interchangeable properties. Neither is harness and the tensile and fatigue properties.

Although 6061 and 2018 have comparable properties (after all, to some folks they are both heat treatable aluminum), they are NOT interchangeable should you be in the market for an alloy for forged pistons.

In some cases, metal that "rusts, sinks and is magnetic" is quite adequate for an application. However, for other situations, you better be more specifice with the alloy and the H/T specs.

Just looked up tribology.....So i'd better watch out for the composition for brackets and mounts etc...... On a side note how many who voted "I'd cast it if I could" have looked deeper into casting?

It all depends on the application. If it is a seriously stressed part that will see high cyclic loads, on which someones safety depends, beware of using melted down drink cans in your back yard wood burning furnace.

But if you are making junk jewelry, toys, or art objects, I say go for it..........

I have never been keen on the idea of buying premium heat treated billet or plate stock, just to turn 90% of it into metal shavings, just to turn up a dumb spacer for something.

Do it yourself primitive back yard metal casting can be very useful. But as Clint Eastwood said in the movie Dirty Harry, " A man should know his limitations".

Hi Warp, 100% agreement.
Depending on your integrity and reputation in the tendering industry, if the customer specifies XYZ material to condition XX and you supply a mixture of Coke cans and old gearbox castings, then your reputation will go before you and you won't be trusted in the industry.
On the other hand, where the item is not particular, it is still important to get the customer's signature to the contract which will specify the requirements.
Material cost is always a prime factor when it comes to deciding how much a job will cost, when everything else is equal.
The problem only becomes one when YOU recommend a certain material for the job, based on getting the cost down against another tender.
For example, a hypothetical customer requires a set of vice jaws for a milling vice and in order to cut costs you decide to use mild steel, case hardened to .75mm depth.
In this job the case hardening failed because the base material being mild steel was unable to support the hard skin which cracked and flaked off.
The material, depending on the cost, should have been either tool steel or nickel chrome steel suitably case hardened.
This happened to me, because the milling vice I bought second hand had a set of soft jaws that had been chewed to bits over time.
I just happened to have some mild steel bar that might do the job, and so made a set up and had them case hardened .75mm (.030") and ground.
They worked beut, untill I gripped a bit of round hard material, and so we have a set of jaws indented near the middle.
When I get a round tuit I'll make a new set, one of these days.
Ian.

Oh yes, professional integrity and business reputation not to mention ethics, (along with Iso traceability) are these days, extremely important to the professional manufacturer and fabricator that desires to stay in business. That goes without saying.

I can identify more with the amateur racer, hobbyist, or hot rodder building his own "stuff" out in the back shed. This is more where the "cast it if I could" mentality reigns, and it can with caution be very practical.

Why would you risk life and limb dealing with molten metals and toxic fumes ?

Why would you spend countless hours designing and building machines that could easily be purchased ?

Why would you spend your meager savings on homebuilt untested gizmos ?

Why do you squander ALL of your free time doing this stuff ???



Because it's fun.

I'm impressed, a whole thread about Aluminium casting including a few moans about porosity but no mention of de-gassing.
Anyone interested should seriously consider buying a book on home foundry work, with correct selection of source metals & using a relatively cheap commercial crucible you can produce reasonable results for a wide range of parts applications.
A man who knows his current limitations does not have to be one incapable of further research to push back those boundaries,
Regards,
Nick

I guess it really depends upon what use you have for the part as casting alloy's have quite different properties to processed billets. Also depends upon what finish you want. Most foundries here in the UK will only take a job if it is a large run of parts and they can charge for tooling ( huge sums of money ), some places will do one off's in sand but still charge an awful lot, you see it requires real skilled workers to do that and it's a workforce that is shrinking rapidly ( they really don't teach it anymore ).

I was in the position of needing castings a few years ago and in the end it was easier and cheaper to build a furnace, burner and buy all the tools needed and teach myself how to do it (steep learing curve). Now I get the odd request from the foundry suppliers that I buy the raw materials & consumables from.

Converting the current furnace to oil and then I expect to be able to do small iron castings.
----------------------------------------------------------------------
On the subject of what alloy to use, you use exactly what the customer wants ( you buy it along with the tracability and analysis reports ), anything else scrap or second hand stuff is for ornamental use only, failing that you will need a damn good lawyer.

Nick is right about fluxing and de-gassing aluminium. Both libraries and book shops seem to be fairly bare of books on home metal casting, it is not a very popular or widespread hobby. These days, internet is probably a much better resource than books anyway.

Back to fluxing and de-gassing aluminium. The commercial foundries have solved all these problems long ago, and commercial products to do this properly are more or less readily available if you inquire. I am still a very raw beginner, but I did finally track down one company with a nearby sales branch called Foseco that supplies castable refractory, and many of the special fluxing and de-gassing agents to the industry. The only real problem being that the quantities available are inconveniently large for the casual small amateur home foundry.

Another approach to this problem, might be to visit a commercial aluminium foundry and ask their advice on specific products to use, and where to get some. They may even give you reasonable sized samples to try.

For small quantities of fluxing and degassing materials, check out:
http://www.budgetcastingsupply.com/

They also have some good deals on crucibles and other foundry related supplies.

It is also a good source for metalcasting information.

Nick is right about fluxing and de-gassing aluminium. Both libraries and book shops seem to be fairly bare of books on home metal casting, it is not a very popular or widespread hobby. These days, internet is probably a much better resource than books anyway.

Back to fluxing and de-gassing aluminium. The commercial foundries have solved all these problems long ago, and commercial products to do this properly are more or less readily available if you inquire. I am still a very raw beginner, but I did finally track down one company with a nearby sales branch called Foseco that supplies castable refractory, and many of the special fluxing and de-gassing agents to the industry. The only real problem being that the quantities available are inconveniently large for the casual small amateur home foundry.

Another approach to this problem, might be to visit a commercial aluminium foundry and ask their advice on specific products to use, and where to get some. They may even give you reasonable sized samples to try. I have found over the years all commercial foundries are more than happy to give away "free" advice and indeed materials but then again I am a professional scrounger :) "give and ye shall receive" I've never charged for my time in my hobbies and never will. Nitrogen is available from "Public houses" aka "bars" and it makes a great difference to the pour. Al is a strange material in that it can dissolve much higher melting metals into itself :shrug: very acidic when liquid.

It depends on what your working on...

We make rotational moulds. Some of our customers prefer the finish and tolerances you can get with a machine from solid tool, but sometimes it just doesn't make sense to make it from solid. I usually look at the size of the job.. If it has deep cavities that are gonna be difficult to machine then i would make a pattern and have it cast. If the job is relatively shallow with not too many sweeping surfaces then it makes sense to cut out the pattern making process and machine it straight out of a solid block. it all comes down to time.

DC

You cant ask that without giving some sort of job discription. Some jobs are machine form solid and others are clearly cast. it depends on what your working on. the size/difficulty of what your doing etc..

You cant ask that without giving some sort of job description. Some jobs are machine form solid and others are clearly cast. it depends on what your working on. the size/difficulty of what your doing etc.. Can too! :p For example you want a raising block for a lathe..You can either buy a billet and machine it or just cast some...Simple! I think what you meant was that some things cannot be machined and in fact "have" to be cast....Apples and Oranges :rainfro:

Obviously there are some jobs that fall smack bang in the middle. They can be cast or machine from solid. As i said.... IT DEPENDS ON THE JOB YOUR DOING!!!http://www.cnczone.com/forums/images/smilies/RAINFRO.gif
:rainfro:

Obviously there are some jobs that fall smack bang in the middle. They can be cast or machine from solid. As i said.... IT DEPENDS ON THE JOB YOUR DOING!!!
:rainfro:

Then do whats cheapest...............That depends on what job you're doing. Is it cheaper to cast it...either way....YES because it's almost free.

Have you "cast" your vote?




I think you missed the point ;)

Cast Vs machined, fabricated from machined parts and machined after fabrication are my preferences, making short runs of complex parts is faster by machining as the time to make the pattern needs to be considered. All this talk about aluminium, what about steel? cheap, easy to cut and weld, easy to machine 3 times as stiff as Aluminium, hard wearing, good strength to weight if using low alloy steels, the prehards machine very well. Aluminium has its uses but it can also be fabricated and machined with the right welder and a bandsaw or plasma cutter.

Hi all, one thing a lot of theorisers forget and that is before you can make a casting you must have/make/get a pattern.
Castings don't just happen.

The other thing is once you've made a pattern you must be able to form the mould round it and also be able to extract it from the mould without destroying the mould in the process, which means no long vertical flat sides, tapered sides are required.

All this is very boring, but when all you want is one square shaped part with lots of flat sides and undercuts, plus a few bores here and there, then the casting may be a pain to have to finish off, plus the fact that unless you have a foundry of even the most primitive nature, you will have to send out the pattern, and hope the foundryman will not throw it in the bin.
I won't even mention haveing a core in the casting, as this will seperate the men from the boys like a dead rat at a banquet.

Fabrication gives you the option of making the part in steel which is a lot better for most uses, and the average tool orientated person can become a welder after a bit of practice.

Whichever method is chosen, it is more than likely that the end product will have to be machined.
One of the chief reasons parts would be cast is for repetition purposes and here a well made pattern is absolutely necessary.
Fabrication doesn't lend itself to repetition, unless you like working with an angle grinder doing weld preperations.
There is a meeting point of the methods, and this is called design.
Ian.