I'm planning a scratch build using tinted acrylic, which should be simple enough once I have the right dimensions (motherboard, PCI brackets etc...). The only thing that's playing on my mind is how I'm going to frame the whole thing. I'm not planning on using the acryllic for structural purposes (except for maybe the drive mounts, which will run from the top right down to the bottom of the case), so I need to find something that I can use to act as the frame for the whole thing. I was thinking of using aluminium angle, but I lack the tools to be able to properly cut and rivet it all together. Another thing I thought of was this aluminium framing that you sometimes see on fold-away tables and office partitions, like aluminium angle but with round edges and plastic angle connectors. Sounds a bit tacky, I know, but with some paint it should look good. I would really like to know where I can get some of this stuff, I know what I'm talking about but it's difficult to explain, so I hope someone can understand what I mean. I'll try to clarify later when I get home if nobody gets it. Thanks for looking, hope somebody can help.
Alu angle is easy to cut with a hacksaw (don't know what you Brits call it, but it's a hand saw for cutting metal ) . The only power it needs comes from your arm. You can smooth the cuts easily and quickly with a good file. For an investment of ~$15 US in tools, you can work Alu well. Just requires muscle and patience. I would not trust any plastic connectors in a structural situation. I can just imagine trying to move the case and the bottom falling out. You don't need to rivet it together, screws or nuts and bolts will hold it together well. Some of the peeps here have found some very interesting screws and can direct you to a good source. Whatever you do, good luck with it. And don't forget to post the worklog.
You might also look for the "perspex and alu" log on here. I just read that last night, and he used some cool stuff called "lubix" I think, which reminds me of some of those kids construction kits on steriods. Here's the log!: http://forums.bit-tech.net/showpost.php?p=1706764&postcount=1
Page one of Franklin's Evolution has square aluminum with plastic frame connectors. I've seen another log make the connectors out of plexi. Personally, I say get rid of the aluminum and make a plexi uni-body frame. That's what my Hypnotoad retro fit was about. You could invest in some heavier plastic and make a removable inner cage, or glue thinner stuff into a box frame.
@ ModMinded: I was reading this log last night as well, it seems like a good idea, but I'm sure he milled all of that by himself. @ Cheapskate: This is what I'm getting at: Also Cheapskate you seem to be good at Sketchup, judging by your competition entry, can you tell me how I can get the rounded edge I need to cover that centre piece?
I've never seen anything like that available. Your best option is to find the maker of the furniture in question. You could also raid used office furniture stores. In sketchup: You would need to intersect the 3 curved angles, then delete the extra bits to extract a curved object. It's likely SU will screw it up. You sometimes need to splice lines and properly divide the faces with the line tool.
I'll give this a try when I get home. Do you reckon there's a company that will be able to make something like this, and it not costing a fortune?
Well just about anything that you have custom made will end up costing a fortune, the only ways i could see it being constructed out of aluminum would to ether press it out of a dye, or cast it out of a mold. I would recommend searching around the web for a part like that, its possible someone manufactures it. The last option would be to get a bit of fiberglass and bondo and make it yourself. I suppose you could form a bit of Plexiglas to it and that would work too...
moulding it sounds like a good ieda, it would take a while to get the first corner made by havd from something like wood. then make a cast from it and use that to cast all the corners you need. good luck
Search for custom aluminium extrusion. Extrusions would probably cost about 1000e-2000e with the tooling unless you can find a stock profile. The corner pieces would be most practical milled. Edit: Here's a brochure for a company I used to work for. Check page 45. http://www.purso.fi/downloadable_files/esitteet/purso_standard_profiles_fi_en_2004.pdf
I've found a place that could do the extrusion and another company that could do the corner pieces. Does anyone think that it's worth making the corner pieces out of aluminium, or can I get away with a cheaper material?
If you don't need to have the strength of metal, I'd suggest you get them made in some plastic. Delrin is a popular choice. Although if you want to anodise the extrusions, aluminium corners could be anodised to match them.
I plan on getting them anodised to a dark grey colour, with the corners a little bit lighter. As you can see in the diagram, the channels along the length of the extrusions are for acryllic to slot into. This might somewhat affect the strength of the frame correct?
Yes the channels might affect the strength, but I don't think it will amount to anything. The weakest spots in that construction are probably the tabs in the corner brackets. If you can give me a tab's dimensions I can whiz up some strength estimations.
Here's some more images of the completed model. Thanks Cheapskate for the advice! Exploded view: Exploded view from behind: Countersunk screw holes: Cross-section for extrusion: Assembled model: Assembled view from behind: For Javerh: Dimensions for the tabs: Some dimensions for the extrusion as well: And some for the holes in the extrusion: Edit: Let me know if you can't read the numbers properly, they came out smaller than I expected :/
That profile will have plenty of strength and stiffness. The weakest portions are the tabs on the corner brackets. They are most vulnerable to the bending of the profiles. For example someone sitting on the case. How much the structure can hold depends on the length of the profiles between two corner brackets. Here's a short table: 500 mm 45 kg 400 mm 56 kg 300 mm 75 kg 200 mm 112 kg These are calculated with a safety factor of 2 and assuming the brackets are 6061. The brackets would probably break next to those 5mm dimension-marks on your picture. From what I can tell, the structure is nice and sturdy for a case. Hope this helps.
It does, thanks! However I just made a scale model on Sketchup using these parts, and the whole case is too wide. My case is about 20cm wide, the model is closer to 30cm wide, which won't fit on my desk. I'm in the process of redoing the design, which is basically the same, just with a much smaller radius in the extrusion. Updated pictures asap.
Here are my solutions to this problem: A) Frame based on square tubes and an example which demonstrates what could be accomplished with them. This unique case was build to satisfy special needs . <More pictures> B) Frame based on square bars and a similar but in some way simplified case. <More pictures> I hope it helps...
