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|9th March 2017, 9:07 PM||#16|
Join Date: Aug 2003
Location: South Australia
I'll be posting all my stupid mistakes anyway, haha. I have a great pic coming up where a strip of aluminium got tangled in the circular saw. But if I can help one person avoid the same mistake then I don't mind looking like an idiot.
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|19th March 2017, 10:28 PM||#17|
Join Date: Aug 2003
Location: South Australia
Updates are going to slow down a bit now that my worklog has caught up with my work, but I'm trying to do at least a couple of minutes on it each day.
I finished the last of the drive holes. Quickest way turned out to be rivet the L-strips, nail punch the holes with the template, then do all the drilling on the drill press.
All frames done.
Time to start on the sheet metal. The circular saw I bought came with a rip saw (the one on the right) which has big gaps for cutting lengthways down wood. I replaced it with the one on the left designed especially for aluminium. It has a lot more teeth, they're all in line with each other instead of alternating left-right, and it has those four slots in it so that when it heats up and expands, it doesn't warp. I used sewing machine oil on the blade to keep it lubricated and cool.
I had to install it "backwards" since the teeth point in the opposite direction - my saw blade cuts upwards from below. An interesting side effect is it pulls the material up towards the front cutting edge and it's only held down by the surrounding plate. For thin offcuts of wood this would be no problem, unfortunately with metal this happened:
The strip I was cutting off was pulled into the circular saw and began wrapping itself around the axle. I stopped because it was making a weird noise. Not sure if that was dangerous, but it's certainly not good. The rest of my cuts were thick pieces.
For each case I ended up with two sheets. A wide one 900x340 for the outside, and a narrow one 900x150 for the inside. The 900s are a coincidence - if the case was taller then the thin one would be longer.
Metal folding is mostly measuring and setting up. Lines are ruled with a set square because it has to be ultra precice. I found that leaving the masking tape on didn't affect the fold.
This small brake is fine for the narrow stuff, but kinda struggles on the wider 34cm 0.8mm aluminium. The middle doesn't have quite as sharp a fold than the edges, but it's fine for this project.
Bam, the fun part.
In order to fit the internal sheet for testing, I had to remove the drive pillars. This meant disassembling the Connect-It. I used a car jack for that. It has to be done very steadily and evenly or it risks cracking the corner plastic.
The end plugs were hammered out with a dowel.
For narrow spaces, the Connect-It can be pried apart with leverage. I used some 25mm alum tubing and a block of wood.
The frame is then reassembled without the drive pillars.
The fitting is perfect.
Loosely fitted inside the frame. I had a lot of tolerance on the edges, maybe 1-2cm, but I had to get the fold exact. Each following measurement is done after each fold, since the fold distorts the length. It's good to practice this on scrap so you know how it turns out.
The outer sheet gave me a bit of trouble. It turns out I needed to add 1mm to all the folds, which I didn't realise until the second fold. It was too tight. I ended up taking the frame apart and shaving 1mm off the length of the frame. On the last sheet I repeated my mistake, but only on one side which is arguably worse. Turns out you can shave 1mm off the frame and it still fits nicely and looks square.
With all the sheet folding done, it's time to work on the cutting. I like to start with the most complex parts, cause if anything's going to go wrong it'll be that. If I screw it up I don't want it to be right at the end.
The golden rule of design is your first idea isn't always your best, so I drew a bunch of ideas (this was for the red case). I tried a bunch of mesh fronts, a bunch of 1 fonts, and some arbitrary designs before settling on a personal preference.
This is the marking out for the 2. I started with an outer box.
Then measured and marked the 2 on it.
Then shaded in the area to be cut, so I wouldn't accidentally follow the wrong line. I think this is kind of important.
I'm using a Dremel for this, with one of those awesome metal EZ Lock discs. I know there's a bit of a divide between the Dremel cutters and the jigsaw cutters, but if you have a steady hand imo the Dremel is way better. When I took the red case into the anodizers, he asked me how I was able to get such a clean, straight cut. With this kind of work it's vital that the Dremel doesn't jump, so you need a strong, steady grip and cut very slowly so it doesn't jam.
|7th April 2017, 5:34 PM||#18|
Join Date: Aug 2003
Location: South Australia
Got frontpaged, better take this moment to do an update.
So, I cut out the 2 with the Dremel.
Then used a kind of mini-hacksaw thing to saw through to the corners. It looks like a snapped blade but it actually comes like that with a detatchable handle so you can saw into blind holes.
It needs a fair bit of cleaning up with a file after that.
Other side of the outer case, I drilled holes for the case thumbscrews.
I actually do this differently now. I put the outer case on the frame and just drill straight through the cover and the frame, then thread the hole on the frame.
The inner sheet needs a few bits cut out before I can test fit it properly. More Dremel work, then some filing.
So here's the inner sheet set inside the case frame (with the drive pillars removed). It's held in place with masking tape.
Now for the fan hole. I'm using an 89mm hole saw in a drill press. Wood below and a thin sheet of ply above to keep it really secure and flat. Added a bit of machine oil to the teeth as lubricant to keep it cool. If it gets too hot, the aluminium will flare outwards a bit around the hole, and the hole saw teeth will get blunt.
Doesn't show up very well in this pic, but I've marked holes to screw the inner sheet in place.
Just doing a few crucial stabilising screws for now, then once it's locked down I'll do the rest. No point in drilling 25 holes and finding it's slipped out of position halfway through.
Some of the screws in place. This is solid now, but adding more will reduce any vibrational noise between the aluminium along the seams. Note that the bottom left corner gets a bit narrow - I had about 5mm margin of error on this so that worked out okay. If I needed more accuracy I would need a more perfect fold in the sheet metal.
Putting in the last of the holes. 2.5mm holes for M3 case screws (fine thread), with the sheet aluminium holes being expanded to 3.2mm to give a bit of installation leeway.
This is my tapping kit, by the way. I only needed one of the pieces, but when I bought it I didn't know anything about tapping or what sizes I'd need. It's hard work on the fingers, but a slow drill can do the job just fine. Doesn't need lubrication with the type of thin aluminium I'm using.
With the inner sheet set in place, I could position the fan grille (actually I should have positioned the fan hole at this point). I used a mix of measuring and eyeing.
The PSU hole is tricky because I can't simply trace it. I started with some measuring to cut out a hole where the switch and socket go.
Used the Dremel again.
Now that the PSU is flush up against the case, I can make more precise measurements as to where the screw holes are.
That viewing hole was right on the edge.
The slot for the SAS PCI bracket gets marked too.
Cut with the Dremel. I didn't get a pic of this, but the SAS PCI rectangle section was removed by drilling into both ends, then bending it out with a few tin snip cuts.
Bit removed and edges filed down. The slot near the centre bottom of the pic is for the top of the PCI bracket, and has to be 1mm wide. I used the hacksaw blade again to get the length right.
Unforunately it wasn't quite wide enough, so i widened it with a needle file and a strip of 60 grit sandpaper.
This is how it fits in. A bit crooked, so that needs some more filing.
Needle file, sandpaper, and flat to get this done. More talcum powder to keep the teeth free of metal bits.
On the other side, the PCI bracket gets taped into place for working.
The end is drilled out.
And screwed into the case itself. So instead of having a regular inner sheet case screw here, it goes right through the PCI bracket as well.
On the other end, the PCI bracket will get a screw as well. This makes the SAS card extremely sturdy for plugging into. I can't drill the hole while the frame is assembled, so I'll do that later.
For the case fan I'm using rubber vibration damping things rather than screws. They take a bit of effort to pull through the holes, but they seem durable enough.
Test fit of all the back panel stuff. I made sure the fan screw holes were de-burred so they didn't cut into the rubber grommets. Also, the PSU screws were weird. It looks like they powdercoated all the threads so it was really tight at first and I thought I had the wrong screws.
And now I come to the point where I realise I've forgotten a few things. Like this screw hole below the drive column.
And the top gets one too, but that has to be offset because it's right under the power switch and the cables are going to be diverted through there.
I also had to clean up a few metal edges, like the one below. Technically the Connect-It will fit there, but I really don't want to cut it that close on part of the case that no one will see.
For the in-built case handles, holes need to be drilled in the top of the case conectors. They need to be 8mm in diameter, 9.5mm from the metal. To make sure it's accurate I drilled a 1.5mm hole in the middle, then drilled it out to 8mm using a bit with a centre spike. I kinda like those spikey drill bits. They always seem to be hard to find though.
The reason for the 8mm holes (7mm would have been fine for the handle belting I'm using) is I bought 6mm fishing weights for threading the belting through. So the weight goes on a fishing line and gets dropped through the frame, then the fishing line pulls some synthetic cord through, then the cord pulls the belting through. This gets done later so I'll post more pics then. Needless to say it makes me feel like MacGyver.
Another thing I almost forgot - the out hole for the power button cabling. The cable will run from the switch on the top, through the frame, and come out near the PSU.
For the red case I had this coming out beside the fan (top left of the pic) for neat cable management. But since there's a mess of PSU cables and SAS cables in the case anyway, I just made the power switch cables come out of the ceiling of the case. That means less cable threading which is good because it's kind of fiddly.
That's the last of the sheet metal cutting for case #2. Next step is remove the tape and clean it up. I've done this, but Imgur has stopped working for me so I'll post those pics another time.
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