Metallurgists of BCF...

[nowhere.elysium]

...I require your sorcerous ways.

How good is cast bronze for load-bearing applications? I'm thinking of making a really steampunk 3D printer, and would love to be able to cast some of the non-moving parts from bronze. I'm thinking frame pieces, purely because it'd add a lot to the weight of the moving parts.

If it is workable, is cast bronze readily tappable, or would I have to think of a different way of fitting parts together?

Also, would I be able to use a metal like brass for guide rails? Is it tough enough?
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[dydey90]

Bronze is a lot softer than steel, so the tappings wouldn't hold as much weight. I'm sure somebody will be along with some exact figures and calculations.

Wouldn't it be better to just plate the parts with bronze?
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This post is probably not serious and shouldn't be taken literally.
Past: CBR125,ER6f NINJA 650, ZZR600 Current: VFR750

[nowhere.elysium]

OK, to put it in context; a lot of these bronze parts will be used to replace plastic printed parts; my main concern is whether or not they'll be able to support their own weight properly, when mounted on a rod.
:edit:
Such as the white parts in this picture of my current 3D printer: https://farm8.staticflickr.com/7272/7651984536_a54d2806de_z.jpg
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[CaNsA]

Kinda on topic :S

I was in Liverpool Uni yesterday, spotted this funky 3d printer and thought of you Mr. Gerry sir.

This would be a funky design for a steampunk printer....

edit: bloody autoresize screws the aspect ratio, open the image in a new tab or something.

https://i.imgur.com/9nJ8DNf.jpg

[nowhere.elysium]

yeah, a delta printer would be awesome, but I'd imagine that having bronze parts in there would be too heavy: it'd cause no end of backlash issues.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[pepperami]

I have had a couple of CZ`s in my dim and murky past and they both had bronze bushes as the small end bearings.
So I`m guessing bronze is okay for a certain amount of load bearing?
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I am the sum total of my own existence, what went before makes me who I am now!

[dydey90]

So mostly those scaffold clip type things and the two lumps at the top? I'd say you'll get away with that. The bronze should be at least four times stronger than whatever plastic it may be.

The weight of the two lumps at the top could be a problem though, but I don't know the sums to find out how much of a problem.
____________________
This post is probably not serious and shouldn't be taken literally.
Past: CBR125,ER6f NINJA 650, ZZR600 Current: VFR750

[nowhere.elysium]

Cool. I'd be redesigning a lot of it to account for the extra weight regardless; it can be made much more substantial than it currently is, but my concern was that it'd suffer a lot with the constant vibration and jerky movements.

Looks like I've got a fifth big project happening, then. Summer's going to be busy for me...
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[CaNsA]

[nowhere.elysium]

I don't have access to plating facilities. Unless I start electroplating stuff myself.


Hmm...
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[CaNsA]

[Aff]

I have a 3D model of a Mendel somewhere. I can find it and change all the PLA parts to bronze to give you an idea of what the weights would be if you want. If I get a chance I could chuck it though a simulation to see how it would behave. would need to figure out all the velocities/forces first though.

Also I've used oilite bearings plenty of times and a few cast bronze products in some designs and they are fine under load. Never tried tapping them though.
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Current Bikes:Honda 929RR Fireblade, Honda CD200 Benly (Project), Stomp Z2 140
Electric Bike Project

[nowhere.elysium]

[nowhere.elysium]

I'm thinking that I might just go for rigidity and accuracy, and use a ball screw on the Z, and rack and pinion rigs for the X and Y. This will mean that I can largely stop worrying about weight (provided I don't aim for speed records), and have a bigger/more ornate chassis.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[kramdra]

Are you casting these parts yourself? Have you got a furnace?

Aluminuim would be better especially if weight is a concern. Brass would also be better than bronze and give the steampunk look. Im not sure where one would find lots of cheap bronze scrap, but brass is very easy to find.


Casting aluminuim requires some practise to get right. When finished you could use the printer to make moulds and cast lots of bike parts

[nowhere.elysium]

I have access to a furnace at work, as well as plenty of bronze stock available. Cast bronze gives a slightly darker, more sedate colour tone, which is nice for the bits that I'm intending to use it for. There'll be plenty of brushed brass for highlights and detailing: the bronze will be for the structural components, which will be mounted into the chassis.

I have no desire to make it with aluminium. It completely defies the aesthetic that I'm aiming for.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[Aff]

Can't remember how different yours was, but here's some weights for the original Mendel in Bronze:

https://i.imgur.com/CnGu7dk.png
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Current Bikes:Honda 929RR Fireblade, Honda CD200 Benly (Project), Stomp Z2 140
Electric Bike Project

[Ichy]

Do you know the grade of bronze you will be using? There are about a gazillion alloys to choose from .

I haven't worked with bronze for a very long time but it shouldn't cause you many problems. Very low friction with other metals and a higher tensile and yield strength than plastic. Weight is the one you need to really look into, you might have to compromise velocity to get accuracy.

Generally just use sharp HSS tools when you work it and treat it like brass.
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[Sload]

Should be more then strong enough for that, but as mentioned the mass will be different so how that upsets your rig?

Also, which bronze? Found this but still looking for actual figures https://www.copperalliance.org.uk/copper-and-its-alloys/alloys/bronzes

Alu bronze - https://www.vegasfastener.com/Aluminmum-Bronze.php
tin bronze - https://www.morganbronze.com/PDF_Files/903_spec.pdf

Low carbon steels for ref - https://www.matweb.com/search/DataSheet.aspx?MatGUID=034970339dd14349a8297d2c83134649&ckck=1
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Honda Varadero >> Triumph Speed Four >> Honda CBR1100xx

[nowhere.elysium]

I should also make it clear at this point that I'm not going to be following the conventional mendel design at this stage; I've decided to use direct drive on a rack and pinion, so as to eliminate things like belt stretch, as well as a ballscrew z drive, because of the extra weight.

I have yet to find out which particular flavour of bronze is available here; I rather get the impression that I can pick and choose a bit. There's also the consideration that since it's being cast, I'll have to design my parts around the process somewhat, so I can fine-tune the design to try and account for weight, too.

This is all rather conceptual at the moment, so if it's impossible, then so be it. I just want to make a 3D printer that looks like it belongs in a home, as opposed to the weird plastic and steel constructions that they currently are: I'm a bit tired of the futurist school of design at this point.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[Sload]

In that case, possibly trying to find out which is the most machinable so you can have it faced off if necessary if you are not happy with the finish on the cast components.
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Honda Varadero >> Triumph Speed Four >> Honda CBR1100xx

[nowhere.elysium]

I'm aiming for the slightly hand-made organic look, so I don't really want to be machining it afterwards. The masters for the moulding process are probably going to be either lasercut or 3D printed anyway, so they should be pretty well precise.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[Robby]

Interesting.

My primary concern would be vibration damping, bronze is going to transmit any vibration rather than absorbing it like plastic would, so you might need to factor in some rubber blocks (or cork, to fit the style).

The load bearing factors of oilite bushes may be a bit of a red herring - it's a bush, something tightly sandwiched between a couple of very hard steel surfaces. The force is transmitted through it, but it doesn't need to absorb much force itself. Different case for a long bronze rod with something heavy dangling off it. Should still be plenty strong enough though.

Now go and cast yourself a bronze inlet manifold for the GS, and stick a turbo on it.